Big Jon, the other main UFC ref always warns the fighters before he is going to stop it. He would have been like "Show me something Ken, or I will stop it!". Sometimes thats all a fighter needs to snap out of it mentally and give it all he has to get out of a bad situation like Ken was in. Clearly Ken had another 15 seconds worth of ass-beating in him before it needed to be stopped, but Tito is too strong and aggressive for him. Unless he caught Tito coming in with a lucky punch or knee, he would have lost anyway.