From looking at the plot of The Dark Knight, Event #2 which is currently happening is reminiscent of the boat scene, where two boatloads of passengers are given the choice to kill the passengers in the other boat or spare them. In the scenario, both boats do not choose to kill each other, and thus they all survive. My guess is that, in this scenario, if one player decides to kill another player, or both decide to kill each other, both players will die regardless, so it's best not to kill anyone.