Many years ago, at an airport in the Med where the ATC was run by the RAF, in the wee small hours of the morning the Watch had their "heads down" - mainly in arm-chairs.
A VERY senior non-commissioned ATCO got up and sat at the Tower/Visual control position, donned headset and proceeded to issue landing instructions to a civil airliner. The aircraft was cleared to land and, subsequently, was given taxiing instructions to the civil apron.
The controller took off his headset and returned to his armchair to continue his slumber.
The only problem being that there had been NO aircraft!!!! Spooky or what ....
The fact that this story can be told proves that the chap was monitored throughout, by his fellow controller who thought it was unwise to try and wake our diligent somnambulist.