Slow that down for a lesson in breaking your hand. There is sweet f.a. tension in the fist and it is not lined up like his forearm strength is holding the fist tight. Bashing somebody's temple with that would damage both parties and no mistake. (probably similar style errors have contributed to his damaged RH 3rd knuckle as you can see already. The ready hand position is low and lax, the whole thing is just sloppy.