Flopped straight, deep enough to fold?

[mr giles]

Home game
PLO
Blinds: $0.50/$0.50
4 players

Stack sizes:
SB: $500
BB: $30
UTG: $350
BTN: $120

Pre-flop: (4 players) Hero is UTG with K[img]/images/graemlins/diamond.gif[/img] J[img]/images/graemlins/heart.gif[/img] 2[img]/images/graemlins/club.gif[/img] 2[img]/images/graemlins/spade.gif[/img]
Hero calls, Button calls, SB calls, BB checks.

Flop: Q[img]/images/graemlins/club.gif[/img] T[img]/images/graemlins/club.gif[/img] 9[img]/images/graemlins/spade.gif[/img] ($2, 4 players)
SB bets $2, BB raises to $8, Hero raises to $32, Button raises to $120 (all in), SB raises pot, BB calls all in, Hero ???

This is at the tail end of an all-night session of pot-limit dealer calls. SB is short enough to ignore. Button is a very solid player, but does like to gamble in situations like this. He could have as little as one pair and a big flush draw. SB is drunk, tilted, and on a suicide mission, but he knows that button and I are very solid players and both sober. He isn't making a move here - he has a hand. It is at least a set or smaller straight, and could be as great as A[img]/images/graemlins/club.gif[/img]K[img]/images/graemlins/club.gif[/img]Jx, KQQJ, etc. He looked at the board for about 5 seconds before making his bet, which I read as the "do this quickly before I change my mind" tell.

Assuming that SB always covers me, how deep do I need to be to fold?