To determine the best play, there is much more information needed. How many get paid? When are the blinds going up again? What kind of stack do you have compared to the other two players that you have not mentioned? Reads on the sb (i.e. Is he a chip leader who likes to play table sheriff? Have you seen him call raises and then fold to a push for more chips? How did he get his chips, playing solid, getting lucky, both?) How do you think you rate as a player against the remaining opponents? Why would sb not raise to isolate the short stack (big hand or vulnerable hand willing to fold to more action)? etc.

As it is, the pot has t4200 in it when the action reaches you. You ask if you should push or fold, but under certain circumstances a call could be a reasonable play. It is t1200 for you to call and you should have t5400 after posting the blind. So, to call you would have t4200 behind, or approximately 7 bb. Your call makes the pot t5400, so if you pushed your remaining 4200 the pot would be offering t9600 for the sb to call t4200 or 2.28 to 1. These odds are approximately correct for someone to call you with just one overcard (Ax for instance). However, if you just call, several things could happen. You and the sb could go into check down mode and you could win that way. You could push a non scary flop, giving the sb the same odds but with only 2 cards to come. etc. There is no reason for the sb to bluff a dry side pot, so you can get away from terrible flops without busting on a flip. Sorry for the rambling, but I guess my point is that it is not necessarily a push or fold situation. If you think the sb can find a fold getting large pot odds, then push. If you feel certain he would only cold call the pf raise with a monster, then maybe you can fold. However, I think the right play might actually be to call and try to play poker from there. If you call and have to give up, you still have 7 bb and SOME folding equity (until the blinds go up) which is not that much worse of a position than the 9 bb you will have if you fold this hand. Hope this helps or at least makes some sense.