Job Service North Dakota appealed from a judgment reversing its award of unemployment compensation benefits to Jamesetta N. Rainey. We agree with the district court’s conclusion that Rainey’s conduct resulting in her discharge from employment with Pro-Serve Corporation constituted disqualifying misconduct, and we affirm.
In July 1994 Rainey was employed by Pro-Serve as a fulltime mess attendant at the Minot Air Force Base. Rainey’s duties included cashiering, washing pots and pans, and preparing and serving food. Terraseta Lesmeister, a coworker, was also a mess attendant. On July 18, 1994, Rainey and Lesmeister were terminated from employment for fighting on the job the previous day. Rainey applied for unemployment benefits; Lesmeister did not.
After an initial Job Service determination that Rainey was terminated for misconduct disqualifying her for benefits, Rainey appealed. The appeals referee conducted a hearing at which Rainey and ProServe’s president and project manager testified. The referee determined that Rainey was entitled to benefits:
“The claimant was discharged primarily for an incident that occurred on July 17, 1994. The claimant was struck with a cooking pot by a co-worker following an argument. The claimant took the pot from the co-worker and struck her on the head. The claimant then observed the co-worker grabbing what appeared to be a knife and, in self-defense, took hold of a butcher knife. Both the claimant and co-worker were restrained at that moment. The claimant returned to her duties and, later that day, was discharged for fighting, which is in violation of company policy.
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“According to testimony taken at the hearing, the claimant reacted instinctively and in self-defense after she was attacked by a co-worker. The employer has not established that the claimant acted with wrongful intent or in substantial disregard of the employer’s interests. Therefore, it must be concluded that although the employer may have had grounds to discharge the claimant, the employer has not established that the claimant acted in misconduct....”
Job Service affirmed the referee’s decision, and ProServe appealed to the district court. The court reversed Job Service’s decision, reasoning:
“[T]he decision and Findings of Fact and Conclusions of Law of the Agency are not supported by the evidence in this record. I agree with the Petitioner that even Respondent’s version of the facts cannot sustain a factual finding of self-defense. Mu*376tual combat is not, by definition, ‘self-defense’.
“Further, the Findings totally ignore key parts of the altercation which is the subject of this appeal. Namely, the Respondent continued to fight after instructions to stop and continued to escalate the combat after her opponent was disarmed.”
Our review of a Job Service decision is governed by N.D.C.C. § 28-32-19 of the Administrative Agencies Practice Act, which requires us to affirm the agency decision if: (1) its findings of fact are supported by a preponderance of the evidence; (2) its conclusions of law are sustained by the findings of fact; and (3) its decision is supported by the conclusions of law. Kempel v. Job Service of North Dakota, 531 N.W.2d 311 (N.D. 1995). We review the decision of Job Service, not the district court, id., although here we agree with the district court’s decision.
A person discharged for misconduct under N.D.C.C. § 52-06-02(2) is disqualified from receiving unemployment benefits. Marion v. Job Service North Dakota, 470 N.W.2d 609 (N.D.1991). Although not statutorily defined, the term “misconduct” is defined in our case law:
“ ‘[Misconduct] is limited to conduct evincing such wilful or wanton disregard of an employer’s interests as is found in deliberate violations or disregard of standards of behavior which the employer has the right to expect of his employee, or in carelessness or negligence of such degree or recurrence as to manifest equal culpability, wrongful intent or evil design, or to show an intentional and substantial disregard of the employer’s interests or of the employee’s duties and obligations to his employer. On the other hand mere inefficiency, unsatisfactory conduct, failure in good performance as the result of inability or incapacity, inadvertencies or ordinary negligence in isolated instances, or good faith errors in judgment or discretion are not to be deemed “misconduct” within the meaning of the statute.’”
Perske v. Job Service North Dakota, 336 N.W.2d 146, 148-149 (N.D.1983) (quoting Boynton Cab Co. v. Neubeck, 237 Wis. 249, 296 N.W. 636, 640 (1941)).
Whether an employee’s behavior is misconduct depends in part on the nature of the work and presents a mixed question of fact and law. Holiday Inn v. Karch, 514 N.W.2d 374 (N.D.1994). Our review of a mixed question of fact and law involves a determination of whether the evidence supports the agency’s findings of fact and, in turn, whether those findings of fact sustain the agency’s conclusion. Medcenter One, Inc. v. Job Service North Dakota, 410 N.W.2d 521 (N.D.1987). On disputed facts, we defer to the agency’s findings and consider only whether a reasoning mind could have reasonably determined that the factual conclusions were proved by a preponderance of the evidence. Hins v. Lucas Western, 484 N.W.2d 491 (N.D.1992). When the agency’s conclusion of law regarding misconduct is based on undisputed facts and contradictory inferences cannot reasonably be drawn from the undisputed facts, we review that conclusion anew. Hulse v. Job Service North Dakota, 492 N.W.2d 604 (N.D.1992).
According to Rainey, the incident occurred while she was training a new employee in the presence of Lesmeister and their supervisor, Gladys Stevens. Raymos and Rock, Air Force cooks, also became involved. Rainey testified:
“A. ... I was talking to Gladys, well, Terraseta, whoever was in pots this morning has to clean up, which was Terraseta was standing right there. And Terraseta she turned around, ‘Jamesetta, if you got anything to say, you say it in my face.’ I said, ‘Terraseta,’ I said, T know you’re having a bad day.’ I said, “You know, I’m not the one.’ And the phrase I’m not the one is, you know, you just don’t mess with us, you know what I’m saying? You can’t just pick on us and get away with it. So she turned around, ‘Jamesetta, you got anything to say, you say it in my face.’ And I said, Well, Terraseta, I’m not talking to you, I’m talking to Gladys. This is between Gladys and I.’ And Gladys said, Well, Terraseta, she’s talking to me.’ And Terraseta kept on rambling on and we started going at it. She was saying, Well, just because you big and tall, don’t mean *377all and everything,’ because I am a whole lot taller than her and everything. So, one thing led to another, before I knew it she swung at me. I swung back at her. And then she reached down in the sink. One of the pots had leaked. I grabbed the pot from her from my left hand, put it over in my right hand, and swung it back at her. And to me that was self-defense. I guess I must have lost it or something because she reached in the sink to pull out something else, and I went and got the nearest thing I could find and that was a butcher knife, which, you know, I should say that was wrong. I — I must have just been out of it, you know. I don’t know what it was. I guess from where I grew up at you just kind of just freak out sometimes I guess.
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“Q. ... So she swung at you with a pot, and you grabbed it and you swung it at her?
“A. Yes. I took the pot from her after she hit me with it.
“Q. Where did she hit you?
“A. She hit me like on my arm.
“Q. Okay. And then where did you hit her at?
“A. When I swung it, I guess I popped her on the head because she’s so short. You know, when I swung it back, I guess it must have just went down because she’s a whole lot shorter than me. I guess she’s about 4 foot something. I don’t know, 4 foot or 5 something.
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“Q. Okay. So then anyway, she swung, hit you in the arm, you turn around and grab the pot—
“A. Hold that, and then at that time, as I was swinging, I felt somebody’s arm trying to stop me and pull me back. You know what I’m saying?
“Q. Okay.
“A. So — I just kind of went back and then she took out something, out of the sink with a black handle and it looked like it was silver coming up. And working with pots, you clean everything. And I was thinking a, you know, she’s coming after me with a knife, you know, or whatever, so before I knew it, that’s what I grabbed and I was wrong for doing that. I guess I was just — I wasn’t gonna get until she came after me first....
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“Q. Okay, did you ever see what it was?
“A. No, I didn’t. Because I was just like — I just like went out of it. You know what I’m saying?
“Q. You saw her reach for something with a handle, you saw her pull something—
“A. And I just grabbed something to defend myself, you know.
“Q. Okay. And then you grabbed a knife.
“A. Yes, I did.
“Q. Okay. And then what happened?
“A. Then we were arguing because Ray-mos was holding me back and Rock and Gladys was holding Terraseta. They got Terraseta out the office.
“Q. Okay, so—
“A. So they had Terraseta in the office. I went back to work. I put the knife up and went back to work. I heard people in the background say, ‘Jamesetta, she’s not worth it.’
“Q. Okay. So let’s go back just a minute here now. So, as far as it got then was you grabbed a butcher knife in self-defense?
“A. Yes, I did.
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“Q. [D]id you go after her?
“A. No. Because—
“Q. Did she come after you?
“A. Sergeant Raymos — she was coming toward me and Gladys and Rock pulled her back and Sergeant Raymos had me back.
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“Q. Both of you were restrained then?
“A. Yes.”
We have upheld denial of unemployment benefits to an employee who was discharged for a single incident of physical force or violence where that conduct violated an *378employer rule designed to insure safety and efficiency. Blueshield v. Job Service North Dakota, 392 N.W.2d 70 (N.D.1986). Even without a written rule, courts have denied benefits, holding that an employee reasonably owes a duty to the employer to refrain from fighting on the employer’s premises during working hours. Annot., Employee ⅛ act or threat of physical violence as bar to unemployment compensation, 20 A.L.R.4th 637, § 6 (1983). There are exceptions to the general rule, and when an employee acts reasonably to defend against an unprovoked assault by a coworker, unemployment compensation cannot be denied for fighting on the job. See, e.g., Hodges v. Everett, 2 Ark.App. 125, 617 S.W.2d 29 (1981); Escamilla v. Industrial Com’n of Colo., 670 P.2d 815 (Colo.Ct.App.1983); Smithson v. Review Bd. of Ind. Emp. Sec., 446 N.E.2d 1014 (Ind.Ct.App.1983); Peeples v. Com., Unemp. Comp. Bd. of Review, 104 Pa.Commw. 504, 522 A.2d 680 (1987); Mississippi Emp. Sec. v. McLane-Southern, 583 So.2d 626 (Miss.1991); General Motors Corporation v. Labor and Industrial Relations Commission of Missouri, 653 S.W.2d 702 (Mo.Ct.App.1983). Although an employee has a right to defend against physical assault, an employee’s actions that go beyond legitimate self-defense can constitute misconduct disqualifying the employee from unemployment benefits. See, e.g., Clark v. Com., Unemployment Compensation Bd., 69 Pa.Commw. 625, 452 A.2d 106 (1982); Wolfe v. Commonwealth, Unemployment Compensation Board, 57 Pa.Commw. 255, 425 A.2d 1218 (1981); Unemployment Comp. Bd. of Rev. v. Vojtas, 23 Pa.Commw. 431, 351 A.2d 700 (1976).
Here, Job Service does not dispute ProServe’s characterization of the butcher knife as a “deadly weapon.” Under North Dakota criminal law, a person is justified in using deadly force to defend herself against “danger of imminent unlawful bodily injury” (N.D.C.C. § 12.1-05-03), if it “is necessary to protect the actor or anyone else against death, serious bodily injury, or the commission of a felony involving violence,” but not “if it can be avoided, with safety to the actor and others, by retreat or other conduct involving minimal interference with the freedom of the person menaced.” N.D.C.C. § 12.1-05-07(2)(b). See Sampson v. State, 506 N.W.2d 722 (N.D.1993). But, contrary to what the dissent states, there was no knife in Lesmeister’s hand, and, contrary to what the dissent seems to suggest, whether or not Rainey would have a justifiable defense to a criminal charge such as assault with a weapon likely to cause serious injury, see § 12.1-17-01.1, N.D.C.C., is not the standard. However, this duty to retreat and attempt to avoid an altercation before resorting to deadly force also exists in the civil context. See Restatement (Second) of Torts, § 65(3)(a) (1965) [privilege of using deadly force does not exist if actor correctly or reasonably believes he can safely avoid necessity of defending himself by retreating if attacked in any place other than his dwelling place].
In this ease, Rainey took the pot away from Lesmeister, hit her on the head, and grabbed a butcher knife. Although Rai-ney believed Lesmeister may have been grabbing a knife, Rainey concedes she “was wrong for doing that” and that she “must have lost it.” Both Rainey and Lesmeister had to be held back by others to stop the altercation. Having to be restrained from attacking with a butcher knife a similarly restrained aggressor is the antithesis of self-defense. Rainey’s own version of the incident establishes that the confrontation had escalated into mutual combat. At that point, neither person was justified in using force. See N.D.C.C. § 12.1-05-03(2)(b). We conclude that Rainey’s conduct went beyond self-defense and constituted disqualifying misconduct precluding her from receiving unemployment benefits.
Job Service asserts that, even if Rainey did not act in self-defense, she is entitled to benefits because her “poor judgment in striking a retaliatory blow does not constitute misconduct.” We have recognized that “[a]n isolated hotheaded incident certainly will not necessarily result in disqualification of unemployment compensation benefits because of ‘misconduct.’ ” Blueshield, 392 N.W.2d at 74. But the “retaliatory blows” at issue in most of the “isolated hotheaded incident” cases relied on by Job Service were relatively minor acts of violence in comparison to Rai-*379ne^s actions. See, e.g., Guest v. Administrator, Unemployment Comp. Act, 22 Conn.Sup. 458, 174 A.2d 545 (1961) [claimant struck supervisor who was verbally harassing him]; Garguilo v. Unemployment Appeals Comm’n, 642 So.2d 784 (Fla.Ct.App.1994) [claimant threw pen-sized radio at coworker who had verbally harassed him]; General Asphalt Co. v. Harris, 563 So.2d 803 (Fla.Ct.App.1990) [claimant hit coworker on hand with shovel for throwing hot asphalt pebbles at him]; Toney v. Francis, 618 So.2d 597 (La.Ct.App.1993) [claimant threw carton of milk at coworker who hit her in the back as she passed by]; Demech v. Bd. of Review, Dept. of L. & I., 167 N.J.Super. 35, 400 A.2d 502 (1979) [claimant threw meat roast at coworker who was verbally harassing her].
In Anderson v. Florida Unemployment Appeals Comm’n, 517 So.2d 754 (Fla.Ct.App.1987), also relied on by Job Service, the claimant, who cut the coworker slightly on the hand with a knife after being struck in the ribs with a two-by-four, was found eligible for benefits. To the extent Anderson can be interpreted as equating the attempted use of deadly force with “poor judgment” and an “isolated hotheaded incident” that will not disqualify a claimant from receiving unemployment benefits, we decline to follow it. Rainey attempted to use deadly force against a restrained coworker. Although Rainey may have momentarily “lost it,” we do not believe her excessively violent actions properly belong in the “isolated hotheaded incident” genre of cases.
Rainey was aware of ProServe’s policy against fighting. She grabbed a' butcher knife and had to be restrained from attacking Lesmeister. Even though Lesmeister was the initial aggressor, Rainey’s escalation of the encounter into a life-threatening situation constituted misconduct evidencing a willful disregard of her employer’s interests.
The position Job Service seeks to have us adopt recognizes little or no proportionality between the incident provoking a need for self-defense and the appropriate response to that need. Under these facts the use of a butcher knife is unjustified and disproportionate to the need to defend. Characterization of the use of the knife as an isolated incident trivializes the magnitude of the seriousness of Rainey’s actions.
We conclude that Job Service’s conclusions of law are not sustained by its findings, and its decision cannot be supported by those conclusions of law. The district court judgment is affirmed.
SANDSTROM, J., concurs. MESCHKE, J., concurs in the result. MICHAEL O. McGUIRE, District Judge, sitting in place of LEVINE, J., disqualified.