I have reviewed the video multiple times and to me it seems the guy that got shot at the end was initially pulling away the guy in the red shirt from the fight, (going down the street shown on the screen, then coming back up, then he walked up the street again behind the car) and then ultimately shoulder-scratched the guy in the red shirt, upon which the guy in the red shirt pulled the gun and shot him.
Th guy that was shot (black guy in white shirt) is not the guy who was being beaten by the mob with the bat initially.
To me, it looks like someone who was trying to diffuse an incident, was ultimately shot by the perp.