Seriously, I’m sure she feels awful about it.
But it’s a matter of training and attitude. “Us vs Them” training and attitude result in innocent “civilians” being killed by law enforcement.
I bet she don’t feel near as bad, heck I will bet that she don’t even feel bad but that is neither here nor there, as the kid she murdered. She intended to shoot someone at the first opportunity and the kid just happened to be in the wrong place at the wrong time. Now, she has street creds around the station and soon will be decorated for her bravery and promoted. While the kid will be lying cold in his grave for committing what crime?