There's no way he goes limp you guys are crazy 
Look at Anderson Silva, and Nate Diaz. They take punishment for hours, and come back. What makes them the two best fighters in the UFC right now! Their world-class chin!
I just think in terms of chins theres those guys with heads filled with cement that take a beating and dont get ktfo.. But still lose the fight..and then theres the guys who take a beating but still compose themselves through the beating..which is half heart and half physical gift 