First, it wasn't the last fight, it was a semi-final match. Second, Ken was fighting Pat Smith right after Royce/Jimmerson, so who's to say that Ken even watched that fight? He may have been, and probably was, warming up and concentrating on his own impending fight. Third, Royce didn't submit Jimmerson, he just took him down and stayed in the mount until Jimmerson tapped, and after he threw a bunch of kicks to boot. It's not at all impossible that Ken had no idea that Royce had any submission knowledge, let alone that his grappling game was as extensive as it was. But even if we assume that someone on Ken's team told him at the very least that Royce shot a double on Jimmerson, that still doesn't mean that Ken's going to assume that anyone on that card has anywhere near the submission pedigree that he had. And he easily sprawled on Royce's shot and reversed him by just muscling him over. Ken literally said in his post-fight interview after tapping Pat Smith that the fight was easier than his Pancrase fights "because he doesn't know how to do any submissions." That's what Ken thought the whole tournament would be: A bunch of pseudo-tough guys who have no clue about grappling all of whom he was going to tap in seconds.