[atrainpsu]

It could also come Ten, Ten. People mucking their hand on the flop after getting allin are idiots. There is almost always some sort of runner runner draw. At least twice I've seen ace high get allin vs. a set, and then 2 wheel cards hit and they try to dive into the muck and they are sh*t out of luck.
Anyway, where I used to deal, we were told to muck a hand once a player "mucked" it. Having already seen the hand should technically not affect this. Since the hand was retrieved by the player, it would stay live in most if not all casinos, although I'm sure a floor could rule that the player mucked his hand, and even though he retrieved it, it was still mucked and dead.