I guess since we agree that I should have bet the flop the amount I did and call his push I'll explain my roomate's rationale for checking the flop, when he saw the villain's A 9 diamonds. The board ended up spitting out a 10 spades and a 6 clubs to give him a straight.

My roomate said that if I check to villain on the flop he'd check his flush draw. Then if I bet the turn he'd call with his gutshot straight draw and his 4 to the flush. Then when the board would have 6 7 8 10 and I would either check/bet villain would push and I'd still have around 2000-2500 chips to play with instead of being out of the tournament in 406th place.

Agree with him?