$33SNG Bubble decision vs. chipleader

[tipperdog]

This one vexes me.

4 players left (normal top-3 payout structure). Blinds just increased to 75/150. I am SB with 1,400 chips. Chipleader is BB with 4,000. UTG and UTG+1 both have ~1,100.

Chipleader is not particularly aggressive--he is not playing like a guy with a monster stack. He has picked up big hands at opportune times and gotten paid off. However, very recently (last 10 hands) he has opened up a bit and called some desperation all-ins with marginal hands.

UTG is super-tight. He is trying to fold his way into the money. UTG+1 seems a pretty good player. He will go down swinging.

In the SB, I pick up A6 [img]/images/graemlins/spade.gif[/img]. Folded to me (chipleader in BB). What's the play?