K6 straight on a flushy board

[HermannTL]

No relevant notes, about 45 hands on each.
MP1 was 43/13/1.36
MP2 was 51/0/0.51

PokerStars 0.10/0.20 Hold'em (10 handed) Poker Stars Converter Tool from FlopTurnRiver.com (Format: 2+2 Forums)

Preflop: Hero is BB with K[img]/images/graemlins/heart.gif[/img], 6[img]/images/graemlins/club.gif[/img].
<font color="#666666">2 folds</font>, UTG+2 calls, MP1 calls, MP2 calls, MP3 calls, <font color="#666666">2 folds</font>, SB completes, Hero checks.

Flop: (6 SB) 4[img]/images/graemlins/heart.gif[/img], 7[img]/images/graemlins/heart.gif[/img], 5[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(6 players)</font>
SB checks, Hero checks, UTG+2 checks, <font color="#CC3333">MP1 bets</font>, MP2 calls, MP3 folds, SB folds, Hero calls, UTG+2 folds.

Turn: (4.50 BB) 3[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(3 players)</font>
Hero checks, MP1 checks, <font color="#CC3333">MP2 bets</font>, <font color="#CC3333">Hero raises</font>, MP1 calls, MP2 calls.

River: (10.50 BB) A[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(3 players)</font>
<font color="#CC3333">Hero bets</font>, MP1 folds, MP2 calls.

Final Pot: 12.50 BB

Flop: I have OESD and a 1-card, 2nd-nut FD. With only 3 players it's not clear that a bet is for value. I assume I am not in front. Outs are unclear especially because someone could have a flush or even a straight. I decided to check/call.

Turn: The straight comes in. The numbers don't support it but I was confident that one of them would bet; MP2 obliged and I completed my planned check-raise. Why would I want to risk giving a free card here? Why even assume that I'm in front? The fact that they both call seems reassuring. Looking back, I think that bet/call would be my best line...and a raise would make me consider a puke fold.

River: Looks like a check/call line would be better, but villain only calls.