second nut flush

[robrobdoe]

Flopped the second nut flush, but was met with aggression. Hadn't played with either player much, but they both seemed typically loose-passive.

PokerStars 0.05/0.10 Hold'em (9 handed) Poker Stars Converter Tool from FlopTurnRiver.com (Format: 2+2 Forums)

Preflop: Hero is UTG with K[img]/images/graemlins/heart.gif[/img], 6[img]/images/graemlins/heart.gif[/img].
Hero calls, UTG+1 calls, <font color="#666666">2 folds</font>, <font color="#CC3333">MP3 raises</font>, <font color="#666666">3 folds</font>, BB calls, Hero calls, UTG+1 calls.

Flop: (8.40 SB) 8[img]/images/graemlins/heart.gif[/img], 2[img]/images/graemlins/heart.gif[/img], 9[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(4 players)</font>
BB checks, <font color="#CC3333">Hero bets</font>, <font color="#CC3333">UTG+1 raises</font>, MP3 calls, BB folds, <font color="#CC3333">Hero 3-bets</font>, <font color="#CC3333">UTG+1 caps</font>, MP3 calls, Hero calls.

Turn: (10.20 BB) Q[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(3 players)</font>
Hero...

Also, UTG+1 had only 2.5BB left in stack by turn. So is there merit in continuing to raise and trying to win a side pot with MP3 (who I presumed didn't have the nut flush due to passiveness)?