It is said that the human body does not possess a maximum threshold for pain.
Floid read about this a long time ago. The book he read said that as time passes and the body is subjected to more and more pain, the maximum amount of pain that you can't withstand increases. It wasn't something Floid could ever test out. The only time Floid ever inflicted pain on others was when he was taking martial arts classes and those were in the presence of a teacher so he always had to hold back from going too far.