It's a good point about the allin saying bluff. I think you are probably right. The checked board said to me that no-one had connected in any meaningful way and I didn't think too long as in this kind of situation I think a long pause would have been bad (interested in views on this as well).

As to %ages of outcome with a pot sized bet V the allin, the pot sized bet does raise the prospect of being reraised by someone who smells weakness and fancies venturing 2500 chips to put me to the test, but not 2500 to call me. The fold equity might be attractive?

Undeniably though a factor for me was that if I havn't doubled up in the first 30-40 minutes of an MTT I start to reach for the all in a lot. It's do or die for me, I either like a big stack or no stack in the second hour. Once I am in this mode of play perhaps here I was more eager to push in than was necessary?