If this switch is thrown, a TARDIS will dematerialize immediately. It will then wait in Limbo until the Epsilon Coordinates are inputted and the Transit Switch is thrown. Emergency Dematerializations bypass the Multi-Loop Stabilizer, resulting in "rougher" landings. They can also cause the lights to go out and might burn out the visual stabilizer circuit.

It is possible, but difficult, to alter a TARDIS's time curve (aka Wormhole) and thus its temporal destination - whilst in the Vortex. This is done using the Emergency Dematerialization Switch during a programmed flight, allowing new coordinates to be inputted into the Directional Unit and thus change course.