Small edge w/ AKo?

[steamroller]

If you call and SB folds, you'll be getting just over even money to call. But, if SB is as bad as you say and can call all-in against 2 players for his relatively small stack, he's liable to do it. In that case, you'll be getting close to 2-1 against Ax and the strong hand. Unless CO has AA KK, that's not a bad position to be in.
Of course, are you willing to risk your tourney life at this point? Given the size of your stack, maybe you are.