


The button that allows you to enter this level is active in the Doom 3 BFG Edition version of the map, however, it will simply take you back to the beginning of MAP02: Underhalls. Walk up to the narrow, stone wall in the northwest of this chamber (I), and press on it to be taken to the Xbox-exclusive secret level, MAP33: Betray. Secret exit : after obtaining the red keycard, drop down, and enter the northeast chamber (H) that has just opened.Behind this wall is a small room containing a few Sergeants (G), a combat armor vest, and a teleport shortcut back to the start of the level. At the top of the staircase inside the structure the red keycard is found in, open the west wall just west of the alcove the key was resting in.Open it into a computer room with lots of Zombiemen and Shotgun Guys to kill. Near the middle of the east water river, is an alcove taking you to a door. There are several traps and monster-only teleporters that can roll in Sergeants and other enemies, and getting the red key opens up Imps and Demons. Kill the Sergeants, and press the switch. Open the blue door, go up the stairs, then open the other blue door. Open the door to the north of the river, and follow it north until you come to a blue door. Fall down into the southwest hole, then follow it to the blue key. Turn right into a pool with more barrels and Sergeants. Follow it until you come to a barrel and a Sergeant. You should see a new barricade open to the west of the water. Backtrack to the start, again go south and open the door, this time open the red bars to the right, kill the Sergeant, and press the switch. Go up the stairs, follow the ledge south until you come to the window, RUN to get inside the building, then turn right and go up the stairs, and then get the red key. Backtrack to the start, follow it east, then south, then west, until you come to a brick building. You are in a room with two alcoves, the left one is open, press the switch to open up a barricade to the northeast of the water. From the start point, cross the water river, then turn right, go up the stairs, and open the door.
