109 Party SnG - How bad is this call on the flop?

[DblDownTrent]

Yes it worked out here, but I had to think about it for a long time, and think folding is probably best. Thoughts on flop bet and/or call? Other than mucking preflop, how do you play this one on the flop. No real reads on the 2 villians in this hand.

Party Poker No-Limit Hold'em Tourney, Big Blind is t50 (9 handed) converter

UTG+1 (t865)
MP1 (t900)
MP2 (t820)
MP3 (t2605)
CO (t1265)
Button (t750)
Hero (t980)
BB (t275)
UTG (t1540)

Preflop: Hero is SB with 4[img]/images/graemlins/club.gif[/img], 3[img]/images/graemlins/heart.gif[/img].
UTG calls t50, <font color="#666666">2 folds</font>, MP2 calls t50, MP3 calls t50, <font color="#666666">2 folds</font>, Hero completes, BB checks.

Flop: (t250) 2[img]/images/graemlins/diamond.gif[/img], A[img]/images/graemlins/diamond.gif[/img], 5[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(5 players)</font>
<font color="#CC3333">Hero bets t250</font>, BB folds, <font color="#CC3333">UTG raises to t1490 (All-In)</font>, MP2 calls t770 (All-In), MP3 folds, Hero calls t680 (All-In).

Turn: (t3440) 4[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(3 players, 3 all-in)</font>

River: (t3440) 9[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(3 players, 3 all-in)</font>

Final Pot: t3440
<font color="#009B00">Main Pot: t2560 (t2560), between MP2, Hero and UTG.</font> &gt; <font color="#FFFFFF">Pot won by Hero (t2560).</font>
<font color="#009B00">Pot 2: t320 (t320), between Hero and UTG.</font> &gt; <font color="#FFFFFF">Pot won by Hero (t320).</font>
<font color="#009B00">Pot 3: t560 (t560), returned to UTG.</font>

Results in white below: <font color="#FFFFFF">
Hero has 4c 3h (straight, five high).
UTG has 2c Ac (two pair, aces and twos).
MP2 has 5h 5s (three of a kind, fives).
Outcome: Hero wins t2880. UTG wins t560. </font>