Ahahaha... I'll see if I can't get him to watch the episode with me at some point. I just rewatched the scene in question, and I have one of two explanations... either the Wraith is getting inside John's head (like Todd is attempting to do later) and influences him to fold... or thinks he has Wraithy's number and knows he's not bluffing. I'm tending to lean toward the first explanation myself.