Dead overcards versus a flush draw. What do you do?

[DrewOnTilt]

Live 6/12 game. SB is extremely loose, and she ALWAYS bets her flush draws.

I'm on the button with A [img]/images/graemlins/spade.gif[/img]K [img]/images/graemlins/spade.gif[/img]
MP3 raises, I reraise, SB coldcalls, MP3 calls.

The flop comes 4 [img]/images/graemlins/heart.gif[/img]2 [img]/images/graemlins/spade.gif[/img]2 [img]/images/graemlins/heart.gif[/img]

SB bets. She bets on anything and everything. She could have a four, trip deuces, a small PP, or anything else, but I am nearly 100% certain that she has two hearts in the hole.

MP3 thinks for a minute and mucks his hand. When he folds, he accidentally flashes his cards: the A [img]/images/graemlins/club.gif[/img]K [img]/images/graemlins/club.gif[/img]

Ugh. What to do?