2 over cards are pretty much a coin toss to an under pair.

AK is great when the flop hits you, but don't think its the win all hand. Just like AA you have to fold them if the flop is bad..

Would you keep AA on a flop of 678? probably not.

Same thing for AK I'd drop it on a flop like 678, drop it to the flush, if the board pairs up your probably in trouble too.