Find the documents in X-18

== Walkthrough ==
Warning: entering the lab sends you into an unavoidable chain of events ending in a different location. If you accepted Wolf's razor, you should finish it before entering, or have fun spawning in a bloodsucker-infested tight space after this quest. 
=== First visit to the lab ===
After approaching the X-18 entrance, you'll be warned by the lab's autonomous defense system that some of your artifacts are not allowed inside, and will be degraded into Cobblestones.
This check is one-time, and only applicable to the first visit to the lab; in any subsequent visits throughout the game, you could carry all artifacts you want without them being destroyed. See Artifact decay#X-18 security system for the exact conditions and the list of the degradable artifacts.
In particular, Stone Blood is not on the list, so you can carry a bunch to remove the radiation while you're there. Sparkler is also not on the list.
=== Finding the documents ===
The rest of the quest is mostly vanilla, except for a lot more enemies inside the lab. As you approach the entrance and open the interlock door, a pseudogiant comes out.
After entering, the way back to Dark Valley will be temporarily blocked and you'll be met by a real horde of mutants, among which is a Librarian. The quickest way to deal with them in early game (without wasting lots of ammo or dancing around with Fight gloves) is a Napalm grenade, which has insanely high damage and low range so it can be used indoors safely. It can be bought from Vityok the Raven for 6000RU, or received as a reward for Anomaly photos.
On the level 1, there's a [ locker room] in which you can find an AK-74, GP-25 and some 40mm grenades, which will be useful later to get out of the lab.
To open the code door, look for the scientists' body in the [ toilet]. As you descend the staircase, the second artifact check will trigger.
On the level 2, there's an [ experiment room] in which you can find a RPG-7 and a couple charges, which will also be useful later on.
There's another code-locked door leading to the command center. The code is on the scientist's body inside the [ pseudogiant's room]. As you enter the command center, a pyro-poltergeist will spawn. Kill it, and Marked One will lose consciousness, leading to another vision.
Grab the documents from the command center. You can also take the Symbion recipe next to it, it will come really useful later into the game. Check the [ embryo storage room] for some grenades, ammo and scientific medkits.
After that, a military squad will enter the lab, blocking the way out. Kill them and exit the laboratory. This triggers the next quest, Get out of Dark Valley.
=== Barkeep ===
After escaping Dark Valley through Darkscape, bring the documents to Barkeep to finish this quest.
=== After the quest ===
After exiting the Darkscape and approaching the Rookie Village, your PDA will break. This is a plot-related event, don't ignore it. See Broken PDA for details.
== Notes ==
* Inside the fridge in the pseudogiant room, you can find some Beer of unknown origin. It's a quest item. Just put the cans into your stash somewehere until it's needed.
* After entering the lab, the transition to Dump will be temporarily blocked, so you will be only able to travel to Cordon through Darkscape until the end of Get out of Dark Valley quest.
* Skimpy's attractive cyclic quests are enabled only if you kill the Pyro-Poltergeist. 
== Bugs ==