Hand vs 2+2er, Put the 3rd Raise in on a Bluff?

[Double Eagle]

This is a hand from last night's Stars 11r. Hand in question comes with about 50 left, avg is about 100k, I stand 10th or so. My image up to this point should be pretty rockish as the maniacal stack two to my left has limited my opening opportunities. The last hand I played I opened from the button with AQ, was called by the maniac in the BB and was forced to make a big call on a TT8 board when he fired out on the flop, pretty much putting me in.

The villain in this hand is a well respected MTTer who has been active opening pots, but who I have not seen call a raise yet in the space of 3 or 4 orbits. He has not yet shown down a hand. When he raises my continuation bet, I sense that he is raising just enough to knock me off my hand, and probably has a low/medium pocket that he thinks might be good but is unsure of. Against an unknown I would muck here pretty quickly, but I think this opponent may not be as pot committed as it appears and may fold if I push. Who here makes that play?

PokerStars No-Limit Hold'em Tourney, Big Blind is t4000 (8 handed) converter

UTG (t8040)
UTG+1 (t47195)
MP1 (t68292)
Hero (t153666)
CO (t296983)
Button (t119147)
SB (t138704)
BB (t106777)

Preflop: Hero is MP2 with A[img]/images/graemlins/heart.gif[/img], Q[img]/images/graemlins/diamond.gif[/img].
<font color="#666666">3 folds</font>, <font color="#CC3333">Hero raises to t12000</font>, <font color="#666666">2 folds</font>, SB calls t10000, <font color="#666666">1 fold</font>.

Flop: (t23400) 7[img]/images/graemlins/spade.gif[/img], 7[img]/images/graemlins/diamond.gif[/img], 5[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(2 players)</font>
SB checks, <font color="#CC3333">Hero bets t18000</font>, <font color="#CC3333">SB raises to t52000</font>, Hero ????