Snipers

The two snipers were stuck in a dilemma, as both of them had their weapons trained in roughly where the other one was. But neither knew exactly, they needed the other to move enough to target. But both of them would only move once they were about to take the shot, and they wouldn't do that until they'd spotted the other.

So they were stuck, waiting for something, anything, to break the stalemate. A wild animal, an uncontrollable bodily function, anything.

A rainstorm wasn't really enough, at first, but then a couple simultaneous lightning bolts sniped the problem quite cleanly.