That's a tough one.
My first instinct was to say that based on your read of the opponent and the pot odds
, you have to go for it.
But then I realized it's a dry side pot and you're contesting 3 other players for the main pot. Top pair third kicker is ok but not great for winning a 4-way pot.
But on the other hand, if you have SB beat you're going to win a lot more than the main pot.
If you're confident in your read, then I think you should shove. AK is almost always reraising preflop, and I doubt he would have thought for a long time to call with KQ, 66, or 55, especially if he's loose. I think your only big risks here are the two pair hands, which are kind of trashy hands. More likely is that you're crushing a weaker king, currently ahead of a straight draw, or he made some boneheaded play and has even worse.
Question: How long did it take him to make the bet on the flop?