Every time I hear this I cringe. I'm no drill-pig (ex-RP mind you) so I'm not 100% sure but I dont believe the above command is correct. In fact I reckon this spawned from someone watching the comrade firemen on "London's Burning" a few years ago and then tried it out on a Monday morning muster parade,got away with it and its mushroomed from there. Surely a simple "Fall out!" would suffice?