I love the implied message in various switches.
Your average wall switch is about convenience. It says that it's ready to go on or off with reasonable effort.
The "emergency stop" switch is designed to be as easy as possible to hit. If you're barely hanging on to consciousness, are missing your hands, and have only a vague notion that you really need to push that button, you can smash it with any available body part and it will switch.
The nuke switch is the opposite. It says that you really really really better be sure before you flick this switch. If you aren't alert enough to solve a bit of a puzzle, the switch stays off.