Enter the first door you see. You may want to get the tire iron found near the second door while you’re at it, though. Jump to the past and get the car battery lying on the shelf. Go back to 2012, go back to the hallway, and switch back to 1972. Enter Room A and switch to the future once again. Go through the hole in the far end of the room, and you will find yourself in a room with a decayed skeleton on the table. Pick up the scissors on the shattered display case. Go to the past, and cut the toe tag off the corpse using the scissors. Go to the future and exit the room.