UB $109, Mid pair vs. overbet

[mikeJ]

600/1200+ante (probably 100), 6 handed

Relevant stacks

Me (CO): 25k
Button: 35k
SB: 40k
BB: 25k

I've been pretty tight. Folds to me in CO w/ 8[img]/images/graemlins/club.gif[/img] T[img]/images/graemlins/club.gif[/img].

I raise to 3300, button folds, sb calls, bb folds

Pot is ~8500

Flop = QT7r

SB checks, I check behind.

Turn = 7 completing rainbow

SB shoves pretty quickly putting me AI for 22k. Your move?

SB has not done anything like this before and has seemed to play a fairly solid game up to this point.