According to the version of the story that some of you are inclined to believe, TM was on top of GZ, had him pinned to the ground with GZ unable to get away from underneath, all the while slamming his head into the sidewalk. Right?
Now, I just checked a photo of TM, and my memory was accurate; TM had only two hands, attached to two arms, no more.
How does one repeatedly "slam" onto concrete the head of someone lying on the ground underneath one, someone who has a shaved head with no hair to get hold of? It takes two hands; to "slam" the head into the ground, you first have to raise that head (and actually the shoulders, to get a real "slam") and propel it down. (Not even mentioning the fact that those couple of minor grazes on the back of GZ's head are not at all consistent with a head that was "slammed.")
So, your opponent has his hands full repeatedly lifting part of your body up and slamming it into the ground, and the only thing you are capable of doing with your two free hands and arms is to reach down and get your gun and shoot him in the chest?!
It just doesn't make sense on any level, no matter how hard you try to spin it, unless your only thought is to shoot him.