This is unfortunate for all parties. I don't comment on any of these headlines until I see footage (if I choose to, sometimes it's too much).
The main takeaways for me, for this case is that, if you don't know by now... shyt escalates and can happen fast. The cop had his gun out ASAP after parking, which to me, didn't seem necessary to breakup a fight, but seeing how he started firing, maybe he saw her with the knife off rip.
I try to look at most situations from multiple perspectives. I see a ton of comments on this situation on social and in here, about how he didn't have to shoot her like that. It's almost like people think that knives can't kill you in seconds. If you're a parent of the girl in the pink, would you be fine with your daughter bleeding out from a stab wound while police were present and could have intervened? Just watch how fast everything played out, we all want better policing, however, some of the reactions and expectations are pretty unrealistic when it comes to split second decisions with people's lives in the balance.