It didn't look to me like Tyson lost it initially, just before he marched over to Lewis, he seemed to consider his actions. I think he was trying to get out of the fight.
That's what I was going to say. Punch or no punch, the fact he bit the guy's ****ing leg suggests it wasn't an act.
I doubt that, he also said to another man "Come here so I could **** you in the ass in front of everybody," you should know by now you cant believe everything that comes out of Tyson's mouth.