[WinBig]

I tried to put some #'s on the stacks because the BB figures were getting me confused. Assume the blinds are 10/15:

Before the hand the stack sizes are:
UTG+1 has 1860
MP1 has 1605
Hero has 1500

Pot is roughly 660 going to the flop and the stack sizes are now:
UTG+1 = 1650
MP1 = 1395
Hero = 1290

UTG+1 bets 495 or 3/4 of the pot and MP1 calls. I really have a hard time believing MP1 flat calls 35% of his stack here here getting 2.3 to 1 odds on a flush draw. If he has the nut flush draw a push here seems like a better play. So I think MP1 also has a big pair because his raise preflop doesn't look like a pocket pair that could hit a set on that flop. I think you have 10 outs twice to win. I push.