Appellant Frederick Newman is a police officer whose civil action against the District of Columbia, the Metropolitan Police Department and Police Chief Maurice Turner (referred to collectively as “the District”) was dismissed prior to trial. In his complaint, appellant alleged that the District had violated the Human Rights Act by discriminating on the basis of sexual orientation. The complaint also included common law claims for intentional infliction of emotional distress and breach of contract. We agree with the District that, as a public employee, appellant was required to exhaust the administrative remedies available to him under the Human Rights Act. No such requirement, however, applies to his accompanying common law claims. We reject the District’s suggestion that the common law claims asserted by appellant are barred by the exclusivity provision of the disability compensation scheme set forth in its Comprehensive Merit Personnel Act. Accordingly, while we affirm the dismissal of appellant’s statutory claim of sexual orientation discrimination, we reverse and remand the dismissal of his common law tort and contract claims.1
I
Since 1970 appellant has been employed as a police officer by the District of Columbia Metropolitan Police Department (“MPD”). In August of 1983 he filed a complaint with the Equal Employment Opportunity Division (“EEOD”) of the MPD alleging unlawful discrimination in employment on the basis of sexual orientation. In the District of Columbia, such discrimination is prohibited by the Human Rights Act. See D.C.Code §§ 1-2501 to -2557 (1981 & 1986 Supp.).
The EEOD dismissed appellant’s complaint for lack of probable cause. Appellant then filed his complaint with the District of Columbia Office of Human Rights (“OHR”), again alleging employment discrimination on the basis of sexual orientation. Specifically, he claimed that he was transferred out of the recruitment division of the MPD because of his homosexual orientation. On April 19, 1984, without allowing the OHR to proceed with the case on its merits, appellant voluntarily withdrew his complaint.
On the same day, appellant filed the first of two complaints in Superior Court. Newman v. District of Columbia, Civ. Action No. 4854-84 (D.C.Super.Ct. filed April 19, 1984). In count one of his amended complaint, appellant alleged a breach of contract based on his transfer from the Recruitment Division of the MPD; in count two he alleged intentional infliction of emotional distress; and in count three appellant alleged employment discrimination based on sexual orientation in violation of the Human Rights Act, see D.C.Code §§ 1-2512, -2526 (1981). On August 8, 1984, Judge Hannon granted the District’s motion to dismiss the complaint for appellant’s failure to exhaust his administrative remedies. A timely notice of appeal was filed on September 5, 1984 (Appeal No. 84-1246).
While appeal from the dismissal of his first complaint was pending in this court, *700appellant filed another action in Superior Court. Newman v. District of Columbia, Civ. Action No. 13009-84 (D.C.Super.Ct. filed Oct. 30, 1984). This complaint was substantially identical to the earlier one, except that it no longer contained his statutory claim of unlawful sexual orientation discrimination. The common law tort and contract claims were unchanged. On May 6, 1985, Judge Holmes granted the District’s motion for summary judgment. From the dismissal of this second complaint, a second appeal was taken to this court while the first was still pending (Appeal No. 85-1568).
In this second appeal, the District moved for summary affirmance. The District briefed an additional argument, which in the first proceeding it had raised only orally. As well as arguing that appellant should have exhausted his administrative remedies, the District contended that his common law claims were precluded by the exclusivity provision of the compensation guaranteed to public employees under the Comprehensive Merit Personnel Act. See D.C.Code §§ 1-601.1 to 1-637.2 (1981 & 1986 Supp.). We denied the District’s motion for summary affirmance and consolidated both appeals in our order of March 21, 1986.
For the purposes of this opinion, we need not and do not distinguish between the two proceedings. Reduced to manageable terms, appellant challenges the trial court’s dismissal of a complaint which is grounded upon three causes of action: a statutory claim under the Human Rights Act and two -common law claims, one in tort for intentional infliction of emotional distress, and the other for breach of contract. We address first the dismissal of appellant’s statutory claim under the Human Rights Act.
II
The Human Rights Act makes it unlawful to deprive any individual of equal employment opportunities because of his or her sexual orientation. D.C.Code § 1-2512 (1981).2 The trial court dismissed appellant’s Human Rights Act claim on the ground that he had failed to exhaust his administrative remedies. According to appellant, the trial court erred because, pursuant to § l-2556(a), he was entitled to voluntarily withdraw his complaint from the OHR at any time prior to a decision on the merits.3
This argument has already been made by a public employee, and by one who was in precisely the position that appellant is now. In Williams v. District of Columbia, 467 *701A.2d 140 (D.C.1983), a District of Columbia government employee filed a complaint with the OHR alleging employment discrimination on the basis of sex and age. Like appellant, Williams voluntarily withdrew her complaint and filed suit in Superi- or Court prior to a final agency decision on the merits. As does appellant, Williams argued that the withdrawal of her complaint from the agency did not preclude relief in a judicial forum. That contention failed. For District of Columbia government employees only, we concluded that the Human Rights Act requires the exhaustion of the available administrative remedies. Id. at 142.4
In Williams, we identified the administrative exhaustion requirement for government employees in D.C.Code § 1-2543 (1981).5 That section requires the Mayor to establish procedural rules to govern Human Rights Act claims submitted by public employees and also provides that the agency shall make a final determination in such cases. Speaking of government employees only, we observed in Williams that “[b]y ignoring the established hearing procedures, appellant foreclosed the possibility that her claim might be resolved without recourse to the courts.” 467 A.2d at 142.6 Although generally recognizing the Council’s express rejection of an administrative exhaustion requirement under the Human Rights Act, D.C.Code § 1-2556 (1981), our reading of § 1-2543 led us to conclude that this rejection did not extend to claims made by government employees. 467 A.2d at 142.
Williams must be read in conjunction with Lamont v. Rogers, 479 A.2d 1274, 1278 & n. 3 (D.C.1984), in which we suggested that once a final agency determination has been made a government employee has the right to bring a civil action, under the statute, for damages or for whatever other remedies may be appropriate. But see Williams v. District of Columbia, supra, 467 A.2d at 142; Dougherty v. Barry, 604 F.Supp. 1424, 1442 (D.D.C.1985).
Appellant argues vigorously that Williams was wrongly decided. He maintains that there is neither a legal nor a rational foundation for distinguishing between government and other employees concerning the exhaustion of administrative remedies. Appellant points to the emphatic language of § 1-2556, permitting claimants to withdraw their administrative complaints without prejudice to the subsequent filing of a civil action, and denies that it is in any way overridden by the more veiled references in § 1-2543 to the procedures to be followed by government employees. As examples of decisions which declined to read an exhaustion requirement into federal civil rights statutes, *702appellant cites Patsy v. Board of Regents, 457 U.S. 496, 102 S.Ct. 2557, 73 L.Ed.2d 172 (1982), and McNeese v. Board of Education, 373 U.S. 668, 83 S.Ct. 1433, 10 L.Ed.2d 622 (1963). He insists that “[t]he Council’s intent as expressed in the plain language of the statute should govern, and should be given full effect.” Brief at 11. Appellant invites this division to overrule Williams.
We need not consider the merits of this invitation, as we could not accept it even if we so desired. Only the en banc court, not a division, can overrule a prior decision of this court. M.A.P. v. Ryan, 285 A.2d 310, 312 (D.C.1971); D.C.App. Internal Operating Procedures (I.O.P.) § VIII H. If appellant is unhappy with Williams, that is a matter he must raise with the full court. D.C.App.R. 40; D.C.App.I.O.P. § XI; see generally Kirk v. United States, 510 A.2d 499, 502-03 (D.C.1986).
In light of Williams, the trial court did not err in dismissing the statutory claim of appellant, a public employee who had failed to exhaust the administrative remedies available to him under the Human Rights Act.7
III
Williams establishes that public employees are required to exhaust their administrative remedies on statutory claims under the Human Rights Act. Appellant’s common law claims were also dismissed. Relying on a different theory, the District argues that the dismissal of appellant’s claims for intentional infliction of emotional distress and breach of contract was equally proper. As a public employee, says the District, the sole remedies available to appellant beyond those provided by the Human Rights Act are those provided by the Comprehensive Merit Personnel Act. D.C.Code §§ 1-601.1 to 1-637.2 (1981 & 1986 Supp.) (“the Merit Personnel Act”). In other words, the District contends that the passage of the Merit Personnel Act marked the end of all common law rights for public employees against the District as their employer.8 We disagree.
Before focusing on specific statutory provisions of the Merit Personnel Act, it would be helpful to turn to general principles and historical background. Our analysis begins with a plain reading of the statute. People’s Drug Stores v. District of Columbia, 470 A.2d 751, 753 (D.C.1983) (en *703banc) (initial inquiry is to examine the language of the statute to determine if it is “plain and admits of no more than one meaning”) (quoting Davis v. United States, 397 A.2d 951, 956 (D.C.1979)). In the event of ambiguity, we follow the presumption that the legislature does not intend to take away common law rights unless that purpose is clearly expressed in the statute. “No statute is to be construed as altering the common law, farther than its words import. It is not to be construed as making any innovation upon the common law which it does not fairly express.” Shaw v. North Pennsylvania R.R., 101 U.S. (11 Otto) 557, 565, 25 L.Ed. 892 (1879); see generally 3 Sutherland StatutoRY Construction § 61 (4th ed. 1974).
One purpose of Congress in enacting the District of Columbia Self-Government and Governmental Reorganization Act of 1973, Pub.L. 93-198, 87 Stat. 774 (codified as amended in scattered sections of D.C.Code (1981 & 1986 Supp.)) (“the Home Rule Act”), was to “modernize, reorganize, and otherwise improve the governmental structure of the District of Columbia.” D.C. Code § 1-201 (1981). In order to effect this purpose, Congress inserted into the Home Rule Act a requirement that by 1980, at the latest, the Council of the District of Columbia was to enact a merit system for District government employees. § 1-242.9 After extensive input from a wide range of groups and individuals over a two-year period, the statute required by Congress was passed by the Council, signed by the Mayor on November 22, 1978, and the Merit Personnel Act gradually came into effect thereafter.
As part of the comprehensive coverage mandated by the Home Rule Act, the Council had to provide “employee disability and death benefits, all at least equal to those provided by legislation enacted by Congress, or regulation adopted pursuant thereto, and applicable to such officers and employees immediately prior to the effective date of the system established pursuant to [the Home Rule Act].” D.C.Code § 1-242 (1981). Thus, among its many other provisions, the Merit Personnel Act includes a system of workers’ compensation for District of Columbia government employees. The title containing that system was said to establish “a program of employee’s disability compensation for the District of Columbia.” Committee Report on the Merit Personnel Act, supra note 9, at 202. Consistent with the condition that this system of employee disability and death benefits be at least equal to that provided by Congress at the time the Merit Personnel Act was adopted, the Committee Report explained that “[t]his title is essentially an enactment of current federal law.” Id. The current federal law to which the Committee Report on the Merit Personnel Act referred was the Federal Employees Compensation Act, 5 U.S.C. §§ 8101 to 8193 (1982) (“FECA”).
The District argues that by adopting the disability compensation scheme set forth in the Merit Personnel Act, the Council stripped appellant of the common law rights alleged in his complaint. If the District is correct, then appellant’s tort claim was properly dismissed.10 Bearing in mind both our principles of statutory construction and the settled meaning of the federal counterpart upon which the District’s Act *704is modelled, we now turn to the specific provisions of the local law.
The relevant provisions of the Merit Personnel Act provide for disability compensation for District employees injured while in the performance of their duty. D.C.Code §§ 1-624.1 to 1-624.46 (1981 & 1986 Supp.). For the most part the disability compensation provisions of the Merit Personnel Act track those of its federal fore-runner, FECA.11 Significantly, the two statutes are identical in their definition of what injuries are to be compensated. Subject to certain exceptions, both provide that the District of Columbia and the United States, respectively-, shall pay specified compensation “for the disability or death of an employee resulting from personal injury sustained while in the performance of his [or her] duty.” Compare D.C.Code § 1-624.2 (1981) (Merit Personnel Act) with 5 U.S.C. § 8102 (1982) (FECA).
The Merit Personnel Act and FECA also contain an identical provision excluding certain common law remedies against the government for disabilities within the compensation scheme. The exclusivity provision of the Merit Personnel Act reads as follows:
The liability of the District of Columbia government or an instrumentality thereof, under this subchapter or any extension thereof with respect to the injury or death of an employee, is exclusive and instead of all other liability of the District of Columbia government or the instrumentality thereof ... in a direct judicial proceeding, in a civil action, or in admiralty, or by an administrative or judicial proceeding under a workers’] compensation statute or under a federal tort liability statute....
D.C.Code § l-624.16(c) (1981); compare id. (Merit Personnel Act) with 5 U.S.C. § 8116(c) (1982) (FECA).
We have never had occasion to determine the scope of the Merit Personnel Act’s exclusivity provision. We have, however, done so with respect to the identical section of the federal scheme which formerly governed the remedies available to District of Columbia public employees. Because the language of the statutes is identical, and because the legislative history reveals that the Merit Personnel Act’s compensation provisions are “essentially an enactment of current federal law,” FECA decisions are entitled to considerable deference in determining the meaning of the Merit Personnel Act.
The FECA decisions shed valuable light on the purpose underlying the exclusivity clause. The Supreme Court has described the philosophy behind FECA’s promise of guaranteed recovery and its simultaneous exclusion of certain common law remedies as the compromise “commonly found in workers’ compensation legislation.” Lockheed Aircraft Corp. v. United States, 460 U.S. 190, 194, 103 S.Ct. 1033, 1036, 74 L.Ed.2d 911 (1983). Public employees are guaranteed the right to receive immediate, fixed benefits, regardless of fault and without need for litigation, in return for which they lose their right to sue the government. Id.; see also H.R.Rep. No. 836, 81st Cong., 1st Sess. 23 (1949) (legislative history of FECA’s exclusivity provision); H.R.Rep. No. 739, 81st Cong., 1st Sess. 14-15 (1949) (same). The adoption of the exclusivity provision in the Merit Personnel Act manifests a similar intent on the part of the District of Columbia legislature.
Nonetheless, it remains the case that government employees only lose common law rights of recovery if the statute *705provides redress for the wrongs they assert. Put differently, the exclusivity provision replaces common law with statutory remedies. It does not take away common law remedies without giving something back in return. The disability compensation scheme is a quid pro quo. As the legislative history of the Merit Personnel Act makes clear, § 1-624.16 “states the limitations on the right of employees to receive other compensation [from the District of Columbia] while receiving compensation under this subchapter.” Committee Report on the Merit Personnel Act, supra note 9, at 204 (emphasis added).
For the exclusivity provision in D.C.Code § l-624.16(c) (1981) to come into play, therefore, five elements must be shown: first, there must have been a “personal injury” within the meaning of the Merit Personnel Act, §§ 1-624.1(5), -624.2; second, the victim must be an “employee” of the District of Columbia government, §§ 1-624.1(1), -624.2; third, the injury must have been “sustained while in the performance of [the employee’s] duty,” § 1-624.2; fourth, the injury must either have caused death or else a “disability” within the meaning of the Merit Personnel Act, §§ 1-624.2, -624.5, -624.6; and, fifth, the injury must not have been caused by any of the three exceptions listed in the Merit Personnel Act — the employee’s “willful misconduct,” “intention to bring about the injury,” or “intoxication,” § 1-624.2. See generally Tredway v. District of Columbia, 403 A.2d 732, 735 (D.C.) (discussing provisions of FECA identical to those contained in the Merit Personnel Act), cert. denied, 444 U.S. 867, 100 S.Ct. 141, 62 L.Ed.2d 92 (1979); Mason v. District of Columbia, 395 A.2d 399 (D.C.1978) (same).
In the present case, it is undisputed that appellant is a District of Columbia government employee, that his grievances were allegedly sustained while in the performance of his duty as a police officer, and that they were not caused by any of the three exceptions specified in D.C.Code § 1-624.2 (1981). Our inquiry therefore focuses on whether his common law claims against the District are grounded upon a “disability” resulting from a “personal injury” for which the Merit Personnel Act provides guaranteed compensation, simultaneously excluding a tort action against the District. The answer is no. Our decision in Mason v. District of Columbia, supra, 395 A.2d 399, compels the conclusion that public employees do not lose their common law rights to sue for the injuries appellant alleges, because neither those injuries nor their consequences trigger the guaranteed compensation provisions of the Merit Personnel Act.
In Mason, a District of Columbia government employee sued the District and its police chief for assault and battery, false arrest and false imprisonment. She sought damages for “mental suffering,” “humiliation” and “embarrassment” allegedly caused by the defendants. Id. at 402. There, we rejected the District’s argument that Mason’s alleged nonphysical “injuries” were within the ambit of FECA, and her common law claims therefore barred by its exclusivity provision. Id. at 403. We also noted that Mason had never alleged the existence of any “disability” which would trigger compensation under FECA. Id. at 404. In both respects, we held that the trial court had erred in dismissing her civil complaint.
Our conclusion that Mason’s allegations against the District — the infliction of “humiliation,” “embarrassment” and “mental suffering” — did not amount to an “injury” for FECA purposes compels us to reach the parallel conclusion here. Appellant’s allegations — the infliction of “humiliation,” “embarrassment,” “public ridicule” and “personal indignity” — do not amount to an “injury” under the Merit Personnel Act. Appellant’s alleged injuries do not fall within the ambit of the statute. And, equally fatal to the District’s case, appellant has never alleged the existence of a “disability” resulting from the psychic injuries he claims. For both reasons the Merit Person*706nel Act is not a source of guaranteed compensation.
Thus, the trial court erred in dismissing appellant’s common law claims. Because appellant does not allege an “injury” causing a “disability” which, in combination, would entitle him to guaranteed compensation under the Merit Personnel Act, the exclusivity provision in § l-624.16(c) of that statute has no effect on his ability to exercise whatever common law rights are available to him.12
Under Williams, we are bound to affirm the dismissal of appellant’s employment discrimination claim under the Human Rights Act. Under Mason, we are bound to reverse the dismissal of his common law claims; those we remand for further proceedings consistent with this opinion.
Reversed in part; remanded in part.
. The District challenges our jurisdiction to hear appeal No. 84-1246. It argues that the notice of appeal was not timely filed, counting the relevant time frame from the date of a dismissal order later vacated by the trial court because it resulted from a clerical error. The District is in error. The trial court dismissed the case a second time on August 8, 1984, and it was this second dismissal which started time running for purposes of filing the present appeal. The appeal was duly filed on September 5, 1984, within the thirty day period following the relevant order of dismissal. D.C.App.R. 4(a)(1).
. That section of the Human Rights Act provides, in relevant part:
(a) General. — It shall be an unlawful discriminatory practice to do any of the following acts, wholly or partially for a discriminatory reason based upon the race, color, religion, national origin, sex, age, marital status, personal appearance, sexual orientation, family responsibilities, physical handicap, matriculation, or political affiliation, of any individual:
(1) To fail or refuse to hire, or to discharge, any individual; or otherwise to discriminate against any individual, with respect to his [or her] compensation, terms, conditions, or privileges of employment, including promotion; or to limit, segregate, or classify his [or her] employees in any way which would deprive or tend to deprive any individual of employment opportunities, or otherwise adversely affect his [or her] status as an employee. [Emphasis added.]
Another provision makes it an unlawful discriminatory practice to aid, abet, invite, compel or coerce the doing of a prohibited act. D.C. Code § 1-2526 (1981).
. That section of the Human Rights Act provides:
Any person claiming to be aggrieved by an unlawful discriminatory practice shall have a cause of action in any court of competent jurisdiction for damages and such other remedies as may be appropriate, unless such person has filed a complaint hereunder: Provided, that where the [OHR] has dismissed such complaint on the grounds of administrative convenience, or where the complainant has withdrawn a complaint, such person shall maintain all rights to bring suit as if no complaint had been filed. No person who maintains, in a court of competent jurisdiction, any action based upon an act which would be an unlawful discriminatory practice under this chapter may file the same complaint with the [OHR]. [Emphasis added.]
. Neither here nor in Williams does it appear that the complainant attempted to refile the voluntarily withdrawn complaint with the OHR before filing the civil action. If they had done so, and the OHR had dismissed the complaint on the grounds of administrative convenience, then their administrative remedies would have been exhausted and Williams satisfied.
. That section of the Human Rights Act provides:
Notwithstanding any other provision of this chapter, the Mayor shall establish rules of procedure for the investigation, conciliation and hearing of complaints filed against District government agencies, officials and employees alleging violations of this chapter. The final determination in such matters shall be made by the Mayor or his designee.
At the time appellant filed his complaint with the OHR, the rules of procedure referred to in the quoted section, governing complaints of discrimination in the District of Columbia government, were contained in Mayor’s Order 75-230, D.C.Stat. 510-28 (1975). The current rules are contained in Equal Opportunity Rules Governing Complaints of Discrimination in the District of Columbia Government, 31 D.C.Reg. 56-79 (1984). Neither the former nor the current version of these procedural rules states that D.C. Code § 1-2556 (1981), the section of the Human Rights Act which permits voluntary withdrawal of OHR complaints, is inapplicable to District government employees.
.In McKart v. United States, 395 U.S. 185, 193, 89 S.Ct. 1657, 1662, 23 L.Ed.2d 194 (1969), the Supreme Court described the fundamental purpose of the exhaustion doctrine as “the avoidance of premature interruption of the administrative process.” See generally 4 K. Davis, Administrative Law Treatise § 26.01 (2d ed. 1983).
. If the merits of the sexual orientation discrimination claim had been reached, the legislative history of the original human rights regulation, 34 DCRR §§ 1 to 35 (1973), might have proved valuable. One of its stated purposes was to ensure ready redress for police officers, such as appellant, who have been discriminated against by the District government:
We urge, with the adoption of this regulation, that a priority be established to assure that the District government will be the first to comply completely with its spirit. Many vital steps have already been taken to this end, however the journey is far from complete. For instance, there is the issue of complaints of discrimination against police officers.
D.C. City Council, Comm. Report on Title 34, "Human Rights Law,” 2 (Aug. 7, 1973) (emphasis added) (available in the District Building).
The Council’s 1973 intent is indicative of that behind the Human Rights Act of 1977, because elevation of the pre-Home Rule regulation onto a statutory footing was designed only to "put our human rights law on a firm legal footing" and "to give that law the increased dignity and force of a statute.” Council of the Dist. of Columbia, Comm. Report on Bill 2-179, “The Human Rights Act of 1977,” 2, 4 (July 5, 1977) (available in the District Building).
. The District makes no argument that the Human Rights Act — as opposed to the Merit Personnel Act — abrogates the common law rights of injured individuals. Nor could that argument persuade. The Human Rights Act was designed to expand the remedies available to victims of discrimination, not merely to divert their grievances into a new channel. Cf. Alexander v. Gardner-Denver Co., 415 U.S. 36, 47-49, 94 S.Ct. 1011, 1019-20, 39 L.Ed.2d 147 (1974) (federal antidiscrimination statute, Title VII of the Civil Rights Act of 1964, 42 U.S.C. § 2000e et seq. (1982), does not abrogate common law remedies). In the earlier proceeding here, the trial court erred in relying upon a theory that appellant was obliged to exhaust administrative remedies on his common law claims. On his non-statutory claims, there were no administrative remedies that appellant could exhaust under the Human Rights Act. The District has abandoned this argument on appeal.
. Congress thus responded to mounting criticisms of the District’s pre-Home Rule personnel management system, criticisms which culminated in the 1972 Report of the Nelsen Commission. Report of the Commission on the Organization of the Government of the District of Columbia, H.R.Doc. No. 317, 92d Cong., 2d Sess. (1972) ("the Nelsen Report"); see generally Council of the Dist. of Columbia, Comm. Report on Bill No. 2-10, "District of Columbia Comprehensive Merit Personnel Act of 1978,” 12-13 (July 5, 1978), reprinted, in House .Comm, on the Dist. of Columbia, 96th Cong., 1st Sess,, District of Columbia Government Comprehensive Merit Personnel Act of 1978 and Report of the Council of the District of Columbia 135-36 (Comm. Print 1979) ("Committee Report on the Merit Personnel Act”).
. As we explain below, it is unnecessary for us to separately discuss appellant's breach of contract claim. See infra note 12.
. We note that the Home Rule Act does not prohibit the Merit Personnel Act from providing coverage greater than that contained in the preexisting federal legislation. Contrast, e.g., D.C.Code § 1-624.28 (1981) (providing judicial review for District of Columbia government employees under Merit Personnel Act disability compensation scheme) with 5 U.S.C. § 8128 (1982) (precluding judicial review for federal government employees under FECA disability compensation scheme); see also Smith v. D.C. Dept. of Employment Servs., 494 A.2d 1340, 1343-44 (1985).
. Our discussion focuses on appellant’s tort claim. The exclusivity provision of the Merit Personnel Act is designed to exclude common law redress for certain injuries leading to disability. That provision will, in most cases, be raised in the context of a tort action. In light of our conclusion that appellant's tort claim is not barred by the exclusivity provision of the Merit Personnel Act, we need not decide here the more complex question whether a breach of contract claim, sharing the same factual setting as the tort claim, might also be barred by the exclusivity of Merit Personnel Act remedies.