Something that might be pertinent about all the shots being fired:
I've been told that, when an officer discharges his firearm, other officers are instructed to follow suit. One, if one officer is firing, then it signals - by definition - that a perpetrator needs shot, and if the idea is to stop the perpetrator then two or three cops shooting him is, in theory, better than one, if the idea is to stop the guy. Two, if more than one officer shoots someone, then the cops aren't sure who killed him and therefore don't have to bear that psychological burden down the road.
Caveats: I don't if what I was told was just complete bullshit; I'm not a cop, I'm not an expert on cops, and I don't pretend to be. Also, I don't even know if more than one cop discharged his weapon in the video.