After you save Rupert from No.9 in the Akropolis Tower stay in the chapel until you find a door on the side. Try to open it and you'll start hearing static and it will flash to a scene with a S.W.A.T member talking to someone. When the S.W.A.T member leaves go inside and go to where he was standing and you'll see he planted a bomb. Try to open the door he left from, its locked but try again and you will recieve a black card. This card is useless until you get to the shelter later on in the game but when you get to the shelter go to the Armory and use it on the card reader. It will open and you will get a refill box of buckshots, a refill box of p.b. rounds for the hand guns, a refill box ofp.b. hydra for the hand guns, and a special shotgun , better then the one you already have now. You will also be able to open that door in the food storage room.