"I've just overheard a secure access transmission. Soldiers have arrived, and they're coming to help us!"
Having failed to escape via the tram, Gordon finds a working elevator that brings him up to the office areas of Black Mesa, which have been similarly overrun by aliens. As he makes his way through the office complex, Gordon encounters many surviving scientists and guards, optionally bringing some of them along to form a posse of survivors (who must be left behind anyway at the chapter's conclusion), and hears that the military have arrived on the facility's surface. He then finds a disabled elevator shaft, and has to climb up it to reach the next area.
This Chapter contains examples of:
- Anyone Can Die: Gordon's optional "entourage" of scientists and guards can easily be slain by the odd Bullsquid or Barnacle.
- Book Ends: The chapter begins and ends inside an elevator.
- Creator Cameo: Gabe Newell's office can be seen here.
- Door to Before: A locked door brings the player back to the cafeteria area after they've traversed the walk-in freezer section.
- Hazardous Water: One office is lightly flooded, but with a live wire going into the water.
- Hell Is That Noise: The aliens make a variety of eerie sounds when unseen.
- Hope Spot: A scientist notes that the military has arrived to help. Sadly, as later chapters reveal, their hopes are very misplaced.
- It Can Think: The Alien Slaves stage what appears to be an ambush in this chapter, with a large team of them occupying a cubicle area and lurking around corridors, implying the possibility that some of the aliens might be intelligent and sinister.
- Mysterious Watcher: This time, he's on the other side of a locked door.
- Optional Party Member: You can choose to bring a bunch of security guards and scientists with you through the complex, which makes the chapter somewhat easier.
- Permanently Missable Content:
- There's a fenced off area filled with supplies that you lose access to if you don't save the security guard on the other side from the Headcrab Zombie that suddenly appears behind him. The security guard would then unlock the fence gate in order for you to enter.
- There's also a scripted event with a Headcrab Zombie that's trying to break out of a storage room. If the Headcrab Zombie is killed before it finishes breaking down the door, the player can't get the ammo within the storage room.
- Player Mooks: The aforementioned optional allies.
- Sequence Breaking: Pushing an NPC into the locked exit door of the cafeteria area that's supposed to act as a Door to Before will result in the door opening due to a glitch. Thus, allowing the player to skip the entire freezer portion of the level.
- Sidetrack Bonus:
- If you explore enough, the shotgun can be found early in a side-area loading map that the player doesn't even have to go to in order to beat the level. This side area also has the fenced supply room that you need to save a security guard from a Headcrab Zombie in order to access the supplies within it.
- Just before the cafeteria, there's a locked office filled with supplies. To get there requires you to go through a long crawl-vent side-path, and then drop into the locked office from the ceiling.
- Video Game Setpiece: A frightened scientist dives through a window to escape an aggressing headcrab zombie, and later, another falls to his death after failing to hang on to a ladder.
