Very tough hand. I'm pretty greedy so I might just call b/c that's a hell of a pot and you have a very good hand. You are only 6 handed which makes me even more inclined to fire away in this situation and discount the flush. Seeing how he is "very tight" KK is the worst case and quite possible but why no re-raise preflop. He was trapping w/ AA with As.

OTOH it might be a very good laydown with the possibility of better set, flush and wacky A10 str8.

However, there's a lot of action early in the hand which leads me to believe that they are not on a draw. I would prefer the push on the flop hoping to isolate the other dude and see what happens and ultimately my greed would force me to call.