Look, unless you were there, you don't know the situation.
You have 1/2 second to react. Assume BG reaching for his waistband, I don't know what he is reaching for. Assume he starts moving as COP 1 fires and he hits COP 2 in the arm as he rushes in to make the arrest. Heck I don't know, it doesn't look pretty. We only get what the media wants us to see.
However, the worst error I see is poor shooting. He only hit the BG in the foot. Really? Couldn't hit him in the elsewheres?!!!!