Hawkmoon and Tallpine - one that bothers me a lot is confusing "who" and "that" and I see it all the time, even in supposedly professionally written articles. And some of us with a high school education from 20-something years ago know better too.
Lee - I agree. Trauma is perfectly normal and to be expected. If she felt nothing about shooting someone I'd wonder. That said, I think it might be a little easier to put it to rest knowing that it had to be him or me.
As to there being any question about her firing "warning shots" while probably not a wise move as she likely wasn't thinking about where else those rounds might have landed, I suspect she likely didn't care to wait and see if he'd follow through on coming through her window. Where he might have succeeded in getting the weapon away from her.
This was a positive outcome, no matter how you look at it.