I dont think there is any disputing it was NOT a dive. Did you see how his jaw seriously shattered in the slow motion replays. It was a HARD and direct shot to the soft spot of the chin. I am not saying the rhino didnt have a glass jaw but Tyson definatly broke it. When he fell, he almost collapsed upon his own leg and ankle nearly spraining or twisting it. This is not done by a man taking a "dive". He got knocked the f out.
As for the mouthpiece thing, who knows what people do when they are messed up. The Rhino probably hit the mat and said "Holy SH#$....Im done", and instinctivly took out his mouthpiece. I dont think that is evidence enough that he took a dive.....
My 2 cents, Tyson might be washed up, but it is incredibly fun to watch a gorilla of a man that is clinically insane get set loose in a roped off boxing ring!