This clip is far from clear. There is no way to tell if the perp was moving at the time of the head shot or not. However, he was within a foot of him, with a much better view.
Like you, I would not vote to convict.
Its very very clear, the threat was neutralized.
The head shot is what is going to get this guy in trouble.
Also him throwing his drink and cup at the dead body afterward is not going help.
He’s facing charges for it.
Unless they could show me this guy has a history of behavior that would make me think this guy is a threat to society in general, I wouldn’t convict him for killing this man regardless, but there is no way he’s not facing charges.