This isn't the school playground. This guy was violently assaulted and could have easily been killed by the attacker.
My feeling is he could have held his fire but the way the law reads I think he was justified in the shooting as he easily could have still believed his life was in danger.
The moral to this story is if you escalate a situation into a violent attack you may well get killed in response. The attacker should have kept his hands to himself said his peace to the other guy if he wanted and got in his car a left. If he did he would be alive today but he choose to commit a violent assault and ended up losing his life.
If I were on the jury, the shooter walks. I don't exactly think he had to fire but he was certainly justified in doing so.
The BG was moving away and clearly so when the shot was fired. If the killer just had shot in the air that would have made the deceased run even faster.
This was a destructive moment and will have political consequences, not the least firing up the gun grabbers.
I think what will help in his favor is that he took a single shot, to center mass. It shows he had no intent of trying to kill the guy (if you want to kill someone, you are more likely going to keep pulling the trigger).
He could easily argue that he hit the ground, was momentarily disoriented, saw the guy take a step toward him, pulled his gun, and before he realized the guy was reacting to the gun, he pulled the trigger once.