9 max 180 MTT SnG 1$ hands AKo nut fd, gutshot

It was sowhere between an Early Stage and Middle Stage. Blinds were 100/200 long before the prizes. I think that it was a good spot for a double up that is why we should shove OTF.
I think may be I should have also isolated preflop, but didn't find the reason back then 3.5 bb it is a very big prize and thought that if somebody from the fishy bigstacks would make a move, I would fire back then.
From my observance BB was real nuts so far opening calling with no sence so his his minraise didn't feel strong so I decided to pull off the trigger. I think the mistake was not to raise more than that (to something like 20 bb) and stack off. OTF we are 50/50 against his cbet range (lets be pessimist and assign JJ+, AQ, 1/2 AJ, 1/2KQ) and given the fact we invested much money already shove was a justifiable risk here

This is again a 180 man SNG. So I have moved it to the tournament hand discussion section, because its fits better there.

I would iso 3bet for sure pre-flop. I expect you will end to often multi-way if you call only here.
As played you can maybe even 4bet jam when he 3bet that small, but I think I would only call in position here. His sizing looks suspicious and if you 4bet you need to call his 5bet shove as well.

On the flop I would stack of with the nut flush draw. To much chips already in the pot and maybe he will fold some better hands as well.

Cheers,
SDK1987

Yeah this is a spot where you have to shove, you have sooo much equity and you can easily fold out hands that have a lot of equity against your exact holding or he could just be taking a stab to try to take down the dead money himself. I'll go broke in this spot 100/100 times and feel awesome about it