Heather is part of a four person mining expedition. There is a cave in and the four of them are trapped in the mine. A rock has crushed the legs of one of her crewmembers and he will die without medical attention. She’s establish radio contact with the rescue team and learned it will be 36 hours before the first drill can reach the space she’s trapped in. She’s able to calculate that this space has just enough oxygen for three people to survive for 36 hours, but definitely not enough for four people the only way to save the other crewmembers is to refuse medical aid to the injured crewmembers so that there will be just enough oxygen