Shooting someone in the back and while they are on the ground isn’t exactly defensive.
I wonder if all the details are reported. I have a feeling the deceased did not go to this guy’s home to watch TV and have a few beers /s/.
No one has ever gotten off the ground to return to the fight.
/S/
I’ve never been in a gun fight, but I’ve always imagined the “off switch” is little hard to engage in the heat of the battle, especially if you really believe the person is going to kill you. A sudden, massive overload of adrenaline is probably going to make you do things you wouldn’t otherwise do.