Is Floyd afraid of breaking his hand?

I mean serouisly, why else wouldn't he go for the knock out? At the lower weights he had that killer instinct and finished guys off. I mean we all remember Gatti. Some people on here say he had to much respect for Marquez to dominate him, but how did he not dominate him? If I was a fighter I would rather get knocked out then be clowned with for 12 rounds. He humiliated Marquez for 12 rounds.