Nut flush, went for overcalls on paired board, action explodes behind

[Aironc]

Pacific Poker 25/50c

UTG +3 is new to the table no real reads, MP2 has bet and raised marginal hands before.

Hero is BB with A [img]/images/graemlins/spade.gif[/img]2 [img]/images/graemlins/diamond.gif[/img]

2 folds,UTG3 calls,MP folds, MP1 calls, MP2 calls, CO folds, button folds, SB completes, Hero checks.

Flop. K [img]/images/graemlins/spade.gif[/img]4 [img]/images/graemlins/spade.gif[/img]4 [img]/images/graemlins/diamond.gif[/img]

Checked through.

Turn. 5 [img]/images/graemlins/spade.gif[/img]

Checked through.

River.7 [img]/images/graemlins/spade.gif[/img]

SB bets, Hero calls, UTG3 <font color="red"> </font> raises,1 fold, MP2 <font color="red"> </font> raises,SB folds, Hero??

Good spot to try to go for overcalls? Now when its two back to me call? Cap maybe? Was more worried about UTG3 than MP2.

Also does anyone semi-bluff the turn with nut flush draw plus gutshot? Thanks for replies.