Alyx: That's terrible and I hope—
Vortigaunt: Ow.
Alyx boards a train that should take her to a junction where she can intercept her father's train, but her train stops just beyond the walls of the Quarantine Zone, an area of City 17 that was walled off due to an uncontrolled presence of Xen monsters like headcrabs, barnacles, and worse. Forced to get off and complete her journey on foot, Alyx unlocks the passageway into the Quarantine Zone, where Eli's train is scheduled to pass through.
As she proceeds through the QZ, she temporarily loses contact with Russell and meets a strange Vortigaunt, who tells her that her father is dead. Or will be dead. The Vortigaunt is disconnected from the Vortessence, which has affected his faculties greatly. He asks Alyx to rescue some of his fellow Vortigaunts on her journey, cryptically tells her to "look to the northern star", and offers her a headcrab to eat as she leaves.
This Chapter contains examples of:
- Cloudcuckoolander: The Lone Vortigaunt, who is cut off from the Vortessence, making him even stranger than most.
- Comically Missing the Point: When Alyx asks Russell about the Quarantine Zone, he explains the etymology of the word "quarantine" instead of what's in the QZ she was asking about.
- Forbidden Zone: The Quarantine Zone is filled with signs and posters saying that it is off-limits. The entrance is also blocked by a gigantic metal plug of Combine design, at least twenty feet in diameter.
- Instructive Level Design: Alyx gains a pistol and is walked through the basics of firing and reloading it on locks, then on barnacles (which are stationary targets), then eventually on zombies.
- Weird World, Weird Food: The Vortigaunt offers Alyx "[s]ustenance!" in the form of a headcrab as she leaves.
