If you play scared, you will be run over. You can't worry about the variance, you should keep playing your ranges with appropriate raises. Of course, the bubble and position payouts need to be taken into account due to ICM but your stack size and position will determine the ranges you will raise and 3bet with. In addition, in late stages a lot of players start playing scared so you can take that opportunity to selectively increase your aggression to steal limps and blinds.
Raise, re-raise, 3-bet, all in, that’s how you should play AK in late stages. With out this kind of play, you will never win. Yes sometimes you will lose, but most of the time you will take blinds and the dead money in the middle, and if someone calls, you got pretty good hand with good odds for flipping. Don’t be scared, play!
If you can't bring yourself to open AK then what ARE you opening? Never be affraid to open the top of your range.
Anyhow, my tournament strategy never changes based on the stages unless we are on the money bubble, or there are icm implications - like on the final two tables - other than that I play based on my stack size. You are just naturally going to lose many more tournaments than you are going to win - that is the MTT life. Don't focus on if/when you're going to potentially bust - just focus on the play at hand and whether or not it was correct. Poker is a marathon, not a sprint.