Prompt: train dilemma, a scenario in which a runaway tram or trolley is on course to collide with and kill a number of people (traditionally five) down the track, but a driver or bystander can intervene and divert the vehicle to kill just one person on a different track. Then other variations of the runaway vehicle, and analogous life-and-death dilemmas (medical, judicial etc.) are posed, each containing the option to either do nothing, in which case several people will be killed, or intervene and sacrifice one initially \"safe\" person to save the others.
