A corporal and two airmen are on guard in an armoury with orders to activate the stations siren should the IRA attempt to gain access to the stored weapons. (Sky-lights? - windows in the roof)
We are locked up in an armoury, the walls are dark and grey
The doors and windows shuttered to keep out IRA
But the sky-lights they are open and should the Irish sin
An hand grenade could fall on us without its safety pin
Therefore, should the slightest sound reveal Paddy is afoot
The first thing that will sound from here are the sky-lights clanging shut.