Walk through the dining room into the area with the tiled floor and exit sign.
Walk through the open double doors into a room with a dining table. Walk straight ahead to the next set of double doors. Stop right next to the metal thing on the wall.
Leave the room you are in by using the door nearest to you. Continue walking straight until the end of the next room. Leave this room. Walk forward until you are standing in front of the black door on the right.