The Sargent might end up thanking her for what she did, because if the alledged criminal had caused him to lose it, then thank God she had the nerve to save him from his PTSD. Working bad areas with bad criminal's can cause these things to happen, because separating emotions from duty after so many dealings with criminal's, and them criminal's taking you to your last nerve is a very hard thing to control sometimes. A debriefing and detuning of an officer by experts on these things should be a daily thing for officer's working in high crime area's.
Think about it, you just dealt with a criminal POCrap that done something heinous to say a child hours before, and the next hour you get a call to another stop where a suspect fit's the same profile of the POC you dealt with the day before, and this one is talking shite, blowing smoke, and verbally threatening officers while they are trying to arrest him. It's probably super hard to control your emotions as the daily grind builds up on you. Detoxing in the sense of one having character degradation over a period is needed badly. Time off, rotation, and other such method's of battling a build up is needed, and a comment box with immunity as in anonymous also needs to be in play for such officer's. They need someone the can confide in, and someone they can trust to help them.