The tragedy of the commons refers to a problem that occurs when individuals exploit a shared resource to the extent that demand outnumbers supply and the resource becomes unavailable to some or all.
The evolutionary biologist, Garret Hardin wrote "The Tragedy of the Commons," which was published in the journal Science 1968 and his major concern was overpopulation.
The tragedy of the commons has implications for the employment of resources and sustainability. Depletion of non-renewable resources is an example of the tragedy of the commons in action.
They wanted to get the harder person first. They did the hard thing first and finished with the easiest. also they probably didn't want to get caught by the sniper if they shot the woman first.