To overreact to a supposed emergency. This term originated during World War II, when B-17 and B-24 bombers had a bell-warning system so that the crew could bail out when the plane was badly hit. Occasionally this button would be pushed by mistake and the crew would bail out unnecessarily, even though the plane was virtually undamaged. By extension, the term came to mean acting in needless haste. In the 1950s it gained currency—and a more sinister meaning—when it also referred to releasing a nuclear warhead by pushing a button.