Abort key

An abort key was a specialised type of key, typically used in a control panel of some kind to stop a specific action. One such action was the launch of nuclear weapons. The Seventh Doctor once stopped Morgaine from launching nuclear weapons by, in part, removing the abort key from a launch console and pocketing it. (TV: Battlefield)

On another occasion, Grand Marshall Skaldak operated the abort lock on a nuclear control panel without keys. Instead, Ice Warrior sonic technology was able to act in the place of a key. (TV: Cold War)