With only 11BB you should either push or fold. A2s with 8 players left to act is pretty marginal, and in this particular tournament its a fold. The reason is, there is no ante to fight for, and presumably a lot of players call to much, because its a freeroll. When players call to much, you need to tighten up, and a hand like A2s is especially problematic, because its either way behind or only slightly ahead.
Especially with no antes you could open a little smaller here maybe 2,5BB. It would not have made any difference this time, but it is a better strategy in general. You have other hands, that want to fold to a jam, and then there is no reason to lose those extra 20% chips.
A2 from UTG is little to loose to open, and you make angry player next to you. Any hand you open next he will probably go all in, with 50% of hands, only because he saw with what you open, and this time he was luckyer. I would do same thing, like your opponent. That first hand ended your tournament life, not the second.