Gordon escapes from Residue Processing and ends up at a mysterious laboratory where Black Mesa scientists were collecting wildlife from Xen. Here, Gordon comes across a security guard warning him that the lobby entrance door to make it outside remains locked unless it's given scanner access from a Black Mesa scientist. The Alien Grunt is also introduced here.
Fighting his way through the lab that's crawling with HECU marines and alien invaders, Gordon eventually reaches a laser testing area where he has the option of retrieving a prototype Tau Cannon for the road ahead. In addition, Gordon blasts a massive laser through a concrete wall in order to reach a locked off area where the last few surviving scientists of the lab remain in hiding. Gordon then brings one of the scientists back to unlock the lobby's front door so that he can get outside, and continue his trip to the Lambda complex.
This Chapter contains examples of:
- Door to Before: There's several doors throughout the lab that can't be opened until you've made your way further through the lab in order to open these doors up from behind.
- Escort Mission: You're required to escort a scientist back to the lab's front door in order to open the locked front entrance to get outside. At worst, you only have to kill one newcomer HECU soldier at the end as the player would have killed all the other enemies beforehand.
- Flawed Prototype: A security guard ends up getting gibbed when he over-charges the Tau Cannon, despite the warning from the scientist in the same room who is gibbed along with him.
- Non-Standard Game Over: If all 3 of the lab's surviving scientists somehow die before Gordon has one unlock the lab's front door, the screen for the player blacks out.
- No OSHA Compliance: The unprotected laser projectors on the second floor can't possibly be OSHA-compliant. If someone accidentally walks into that beam...
- Optional Party Member: The security guard near the start of the level who warns Gordon of the lab's situation can be brought along to help Gordon fight through the lab to search for the surviving scientists. The guard even suggest that the two of them should team up.
- Road Block: The front door to get out of the lab remains locked without scanner access from a scientist, which Gordon has to the traverse the whole lab to reach the few lab scientists that are still alive.
- Unintentionally Unwinnable: You can deliberately trap yourself in the rotating door near the end, by triggering the turning process and moving back, then entering the side part of the rotating door.
