... rare, medium or well done?

... looks to be a nuclear bomb arming-set switch. Possibly used on 'tactical' fighter aircraft. Note the choices of ground- burst or air-burst and the metal flanges acting as a simple 'holy-shit' safety on the selector.

A 'ground-burst' of a nuke from such a small, low-flying aircraft would involve a 'lay-down' of the weapon with a parachute and soft landing. A timer would delay detonation until the aircraft had gotten a safe distance away. Always gets my imagination going: cut to scene of elderly babushka lady cursing and beating with rake on H-bomb that has landed on her prize turnips.