This is used in medicine by doctors in training (residents) especially ER residents which means too many patients hit the door at the same time. You get fucked when theres a total piece of shit patient (such as a crack head with a gunshot wound) because they suck up a lot of time. You get clusterfucked when several crackheads shoot eachother and instead of doing the world a favor come into the ER for blood transfusions etc that will unfortuantely save their lives.
Yeah I was about to discharge this sorority hottie and go home when I got totally Cluster Fucked by 4 bangers with multiple GSW to the chest.