99 in BB on the bubble - fold or push?

[unlucky513]

playing the end of a tourney for a friend, i guess it was a $10 20 person SNG on PokerRoom.

there are 5 left, blinds are 300/600 - i have about 6k in chips.

UTG open pushes for 1800ish, folded to SB who has about 11k in chips and he calls. i'm in the BB with 99, what is my play?

at this point all of the action is going on pre-flop, everyone is either pushing or folding.