Anyone who trains in martial arts knows that you only fight in the ring. If you are gonna fight, fight for money otherwise walk away. There are always some crazies that will take you on out of jealousy. The problem is if you take a fall you are done (on the street). It wasn't the punches that killed the dude, it was the impact of his head on the cement. Also any decent human being would stop punching after the dude is lifeless on the ground.