I want to know more about this film before really giving an opinion. I wonder if the "cop" is actually a security guard working the gate of a gated community. His training, if that were the case, would not be the same as a law officer.
At any rate...his mistake was that he was to close to the suspect, and in fact opened the door for the suspect. How he could have gotten around that, I do not know, perhaps keep the car door between him and the suspect. I agree that a normal stop would have had the cop on the driver's side of the car. The cop apparently knew who he was about to deal with, since he was focused on the passenger. Perhaps there was no time for back-up to arrive, eventhough it had been requested. Who can say?
It is telling that the driver left the scene, and an onlooker came running up either to help the officer or the criminal.
If this officer had been able to get a bullet in the head of this criminal I believe he would have been totally justified. I do not need more information to state that. I do think it would have taken a head shot to stop him. The problem, of course is as soon as you unholster that gun in a slugfest or wrestling match, you can lose control of it.
I wish the end of the tape, or just more information was available.