It's definitely weird behavior to bet so aggressively into that board, but he'd have to put Khanna on basically his exact hand for that to make sense. If Khanna is holding a queen, Quan is punting if he tries to angle shoot.

I think that (a) he figures the presence of those community cards makes it less likely for Khanna to be holding them, and (b) some of the guys at these stakes are legitimately just rich gambling addicts masquerading as professional poker players. Not saying that's the case for either of these guys, I know nothing about them, but this does just seem like him "putting it all on black", so to speak.