[5.50] AK w/ top pair on 3 flush board

[rivermetimbers]

Poker Stars, $5 + $0.50 NL Hold'em Tournament, 10/20 Blinds, 8 Players
LeggoPoker.com - Hand History Converter

UTG: 1,320
UTG+1: 1,540
Hero (MP1): 1,460
MP2: 1,440
CO: 1,340
BTN: 1,630
SB: 2,230
BB: 1,040

Pre-Flop: (30) K[img]/images/graemlins/spade.gif[/img] A[img]/images/graemlins/spade.gif[/img] dealt to Hero (MP1)
2 folds, <font color="red">UTG+1 raises to 40</font>, <font color="red">Hero raises to 140</font>, 2 folds, BTN calls 140, 2 folds, UTG+1 calls 100

Flop: (450) 2[img]/images/graemlins/diamond.gif[/img] 6[img]/images/graemlins/heart.gif[/img] 3[img]/images/graemlins/heart.gif[/img] (3 Players - 1 is All-In)
UTG+1 checks, <font color="red">Hero bets 225</font>, BTN calls 225, UTG+1 folds

Turn: (900) K[img]/images/graemlins/heart.gif[/img] (2 Players - 1 is All-In)
Hero checks, <font color="red">BTN bets 300</font>, Hero folds

Results: 900 Pot
BTN mucked and WON 900 (+535 NET)

Often I will shove on this, but I'm pretty sure folding is the correct move. Any help?