I believe there needs to be a different measuring stick besides EV for All-in bets where you put your whole tournament on the line.

Let's say you go broke on a bet that had a positive EV. Sure, you can console yourself with the fact that you'll will win more chips (not money) in the long run if you make that bet every time, but who's to say that had you not gone all-in you wouldn't have gone on to win the tournament?

When you go broke there is an "implied" loss, the maximum of which is the first prize of the tourny.

IMO Just because a bet has a positive EV, doesn't mean it's the right bet for a particular situation in a tournament.

"My last 2 dollars"

Diamond Jim Brady
(After being asked what was his biggest bet)