Tough hand

Getting a bit late on in an MTT, fast approaching the bubble, and this hand happens:

PokerStars No-Limit Hold'em Tourney, Big Blind is t400 (8 handed) converter

SB (t4405)
Hero (t8066)
UTG (t7842)
UTG+1 (t4940)
MP1 (t9890)
MP2 (t4990)
CO (t7276)
Button (t10183)

Preflop: Hero is BB with 6, A.
UTG calls t400, 5 folds, SB completes, Hero checks.

Flop: (t1175) 6, 4, 3 (3 players)
SB checks, Hero bets t7641 (All-In), UTG calls t7417 (All-In), SB folds.

Turn: (t16233) K (2 players, 2 all-in)

River: (t16233) 2 (2 players, 2 all-in)

Final Pot: t16233

Results in white below:
Hero has 6c Ah (one pair, sixes).
UTG has 9h 8h (flush, nine high).
Outcome: UTG wins t16009. Hero wins t224.

I would normally raise this big preflop at this stage when it's limped to me like that, but the UTG guy who limped I had marked down as being a tad tight/passive, so I was hesitant to raise on the flop.

The flop looked beautiful to me, TPTK and the nut flush draw. I think pushing was wrong though as I'm only getting called by a better hand, I can't see people risking all their chips on a flush draw that isn't the nut one at this stage. Kinda unlucky to run into a flopped flush though. I think I was destined to get a dent in my stack from this hand, but the push was wrong, I just wanted to pick up the pot there and thought I was ahead or could get an overpair to fold to the draw-worthy board. Your thoughts?

[a500lbgorilla]

Pot wasn't nearly big enough to justify a push there.

-'rilla

[gabe]

preflop:raising is bad when anyone plays from utg and you have A-rag.
postflop: you had 20bb, i would probably bet about 2/3 of the pot. you do not need to overbet your hand to protect yourself from the draw because YOU HAVE THE NUT DRAW. If you do get raised, i could justify pushing, but I think the push as first to act is bad idea.