It's hard to say without more specifics, but I'd have to say that it would depend on the presentation of said NPC. Sentinel are given a lot of leeway so long as they wear a Tower badge, so if it were a Normal she injured, and she pledged to reform her ways and work for the Tower, there's a decent chance it would be overlooked. If she were a rogue, or if the NPC were a Sentinel, then it would be significantly less likely, and would probably put the rest of the Sentinel police force on her tail. They don't look kindly on cop-killers.
blerrrrgh. So many ideas i has, precious!
Basically - in my brain - I would like her (well, the both of them, really) to have been a pain in the ass for quite sometime. Her being a rogue Sentinel, and him trying his best to help her out. But, short of finding her a Guide or getting her addicted to Guidine(which, obviously not a good idea) he's running out of ideas to try and help calm her when it's obvious she's not getting any better with uh... ~dealing~ with feelings and things. breaksalotofshit. breaksalotofpeople. Ya know?
I suppose Mr. NPC guy could be Normal. Confronts her and she rage-quits on him. More cops show up, Sexy-man-friend-whom-really-needs-a-name shows up, gets her to calm her shit a bit and talks her into just going with them - which she does so very
-cough- Sorry, that mostly seemed like I was talking to myself, I think. But I guess what I'm trying to ask is: Is that a Yay or Nay possible scenario?