MAP07: Frustration (Memento Mori II)

MAP07: Frustration is the seventh level of Memento Mori II. It was designed by David Kuykendall and uses the music track "Midnight Call" by Mark Klem. It contains a separate area for multiplayer competition. It is infamous for featuring a door that does not usually open all the way, forcing the player to use it repeatedly until it opens enough to allow them through.

Mission briefing
According to both the text file and the Infopack:


 * Finally you fight and frag your way out of hell, a sewer tunnel looms before you, light shines at the end. Salvation!  You have beaten them!  Not too hard you think to yourself, a cakewalk compared to last time...  Well, time to go home.  Humming to yourself you sling your shotgun over your shoulder you make your way to the exit, only to find that it is blocked!
 * Well dammit, must be a way around...how bout [sic] this ladder...?
 * Hmmm, maybe your [sic] not done yet...

Secrets

 * 1) When you open the door leading to the yellow keycard, another set of doors will open behind you to reveal two (one on easy skill levels) chaingunners. Enter either one of the compartments they came from, and press on the wall with the lightning bolt on it. It will open to reveal a blue armor. (sector 497)
 * 2) In secret #1, press on the western wall with the lightning bolt on it to find a medikit (sector 531).
 * 3) In the room south of the hallway behind the yellow door, after thinning out the slime flow, enter the door to the east you just opened approaching the computer terminal. Press on either wall with a lightning bolt on it to open two alcoves with a chaingunner each (only one on easy skills). The southern alcove has a wall with a lightning bolt on it, unlike the northern one; press on it to discover a medikit. (sector 291)
 * 4) To access the blue keycard, you must find a switch in a dark, metal room, opening a door leading to a hallway with another switch that enables access to the keycard. In the aforementioned metal room that is in the southwest of the berserk pack, press on the wall with the lightning bolt on it to the south to find a blue armor (sector 543).
 * 5) As you exit the blue keycard room, you will find yet another wall with a lightning bolt on it; press on this one to find a box of shotgun shells. (sector 559)

Bugs
Linedef 367, which is part of the invisible "crusher line" near the start of the level that triggers the "frustrating action" of the frustrating door, erroneously does not have linedef type 141 (W1 Start Crusher Slow, Silent). Hence, once can avoid the "frustrating action" of the door by carefully walking on the southern (right) brown ledge next to the central metal path.

Current records
The Compet-N records for the map are:

The data was last verified in its entirety on May 11, 2014.

Things
This level contains the following numbers of things per skill level:

Technical information
The "frustrating" door works by exploiting the property of doors to open to four units below the lowest adjacent ceiling.

The door (sector 177) actually consists of two merged sectors. One is the door itself, the other is a zero-width sector outside of the boundary of the map. This zero-width sector is adjacent to another sector outside the map, sector 180. Hence, sector 180 would also count as an adjacent ceiling for the purposes of the door.

When the player starts the map, he is likely to cross one of linedefs 358, 362, 364, 369, 371 and 373. These lines all have special 141 (W1 Crusher Start Slow, Silent) with tag 3. Sector 180 also has tag 3 and is adjacent to a sector with ceiling 96 and floor 8 (sector 179), so it begins oscillating between heights of 16 and 96 units.

The neighbouring sectors to the actual door that are within the level geometry (178, 175, 174) have ceilings of 96 units. Thus, since sector 180 is oscillating between heights of 16 and 96 units, it is very likely to be considered the lowest adjacent ceiling for the purposes of the door's operation. Thus, when the player opens the door, the lowest adjacent ceiling is calculated by reference to sector 180. Hence, the door will raise itself to whatever height the ceiling of sector 180 is at that time, minus four units, giving the appearance that the door has jammed at a random height.