What makes you "sort of have him" on AK when he just flats preflop, and raises a c-bet on a Q high board?

His range here if he's decent is usally KQ, AQ, sets, bluffs or maybe he is being spazzy with a worse top pair if he's bad. AK is the very small part of his bluff range that is going to stack off on this turn, but I don't think it's very likely here at all.