IMO, that is why Kai pushes harder than everyone else.
Look at the other crop of top O guys. No offense, but they're not exactly tough as nails. Phil Heath has a computer degree and carries a louis vuitton man-purse. Jay wore the 'golden boy' moniker from minute #1.
Kai,, on the other hand, has seen some seirous shit. And that toughens one up. He's willing to go further cause it's all he had to get out of his situation. Jay could be a personal trainer tomorrow and make a good living, Phil could be a netadmin at the local law firm tomorow and do fine. Kai needs this.