How to Secure a Building:

U S Army
The Army would secure a building by locking all doors, put bars on the windows, and establish one entrance with a guard post and armed guards and carefully check the IDs of all personnel who try to enter.

U S Navy
The Navy would secure a building by swabbing all decks, turn off all coffee pots, turn off all lights, lock all office doors, and lock all entrances as they leave the building.

U S Marines
The Marines would secure a building by assaulting it with a combined arms team, breaking into all interior rooms, shooting all resistance, and planting demolition charges as they evacuate in an orderly manner. They would then level the building to prevent further enemy use.

U S Air Force
The Air Force would secure a building by having the Base Contracting Officer negotiate a three-year lease with a option to purchase.