How is what he did any different from a cop doing a mag dump on somebody who has pointed a weapon at them?
The last shot may have been a result of still seeing body movement when the hand was still close to the weapon.
Baldy had already picked up the perp's "weapon" when he fired the last shot.
rule #1 of engagement.
aim COM, empty magazine. Perp still standing, do it again. Chances are slim perp is wearing armor, especially the idiots that rob a place with a fake gun. Even if they are, taking 9 shots to the torso is going to leave some damage, hopefully enough to incapacitate them, but assume otherwise.