at a BBQ, when there are burgers that have finished cooking but no one is ready to eat them yet, so you push them to a lonely corner of the grill to keep them warm. (burger+purgatory)
Steve: "What do we got on the grill?"
Alex: "We got some dogs, some sausage and a couple of burgers in burgatory over there"
(burger + purgatory) At a BBQ, when there are burgers that have been cooked but no one is ready to eat them, so you leave them on a separate side of the grill to stay warm.