How to Tell the Difference Between the Branches of the US Armed Forces! If you give the command "SECURE THE BUILDING", here is what the different services would do: The NAVY would turn out the lights and lock the doors. The ARMY would surround the building with defensive fortifications, tanks and concertina wire. The MARINE CORPS would assault the building, using overlapping fields of fire from all appropriate points on the perimeter. The AIR FORCE would take out a three-year lease with an option to buy the building.