Of course you werenīt obligated to call, but in my opinion it was the best play on that situation.
The only logic reason that may explain a fold here is that you donīt want to lose 14% of your stack, because you may feel uncomfortable with your game with just 11xBB. But thatīs not enough a good reason to fold there. You have some strong points to make the call, like EV. If youīre against overpair, then the right play should be to fold, but Rob mentioned a very good detail: at that point the players that went all in could have done that with any two face cards. The first player had to go all in with any high card, and the second probably went all in with 2 high cards to keep away more callers. A pocket pair by any of those 2 would be very less probable than having just overcards.
I think that maybe you have a wrong image on what are the odds of winning against overcards. In the situation you told, preflop you had 34% chances of winning the hand, but iīm going to suppose the most probable situation, where your 2 opponents have different overcards. Lets say your 5-9s is against A-10 and K-Q. In that case you have 30% chances to win the hand. Knowing that you donīt have to do any math operation to realize you get a positive EV. Your hand odds are 2.3:1 and your pot odds are 3.6:1. Clearly profitable.
So applying math, that is a must call. But the EV cannot be applied in every situation, especially if itīs in a specific tournament situation. For example, if in a tournament you call a bet for all your chips as the underdog but getting good EV, is a bad call, because thereīs no long term. But if we analize the hand you told gf, if you lose you still have a good stack to play comfortable and if you win you build a nice stack that will allow you to steal more and put more pressure on short stacks.
If you want to win the tournament you have to take those chances at those stages of the tournament. Remember that unless youīre all in there are lots of situations were you want to call being the underdog.
...........wait, i still havenīt won any CC event.....wait until next friday after FTP event and then read this post.