I wonder if this resembles a standard game-theory game. I think the approximate payoff matrix is as follows, if we say -8 for congregating on either side and -2 for anyone on the crocodile side of the plane:
Croc Side | Away Side
CS -10,-10 | -2,0
AS 0,-2 | -8,-8
*starts digging through Wikipedia*
It's not quite a Volunteer's dilemma, because everyone-cooperating is still bad - it's actually an El Farol Bar problem. (Presumably you would be able to react to other's moves, but only after the initial rush - said rush probably already destabilizing the plane.)
An unusual incident. Are you obligated to be on the side of the plane with the crocodile if the other passengers are overbalancing the plane? To push other passengers over to the side with the crocodile?