With the help of his new HECU squad, Shepard fights his way through the Xen aliens of another Black Mesa office area until he's forced to split up from them. He then treks along a path that eventually takes the corporal up to the surface. Along the way, Shepard comes across another radio, which the soldier on the other end is heard calling for reinforcements as they appear to be under attack by the Black Ops, who are supposed to be allies of the HECU.
Out on the surface, Shepard comes across an HECU Medic, who informs the corporal that there's another extraction point at Black Mesa's Lambda Sector. Unfortunately, the nearby door leading to the transit system that will take them to said sector is locked tight; requiring an Engineer to break in. Shepard enters a hanger nearby overrun by Black Ops soldiers where he overhears some of them discuss how they've come to clean up the grunts' mess (referring to the HECU), and that they wanna leave once the "package" is delivered. Said package appears to be a nuclear warhead that they're trying to load into the back of their truck. Shepard goes about killing the Black Ops soldiers in the hanger, and manages to locate a dying Engineer that was hiding in the room. He brings the Medic he met back to the Engineer, who fixes him up.
The Engineer is brought back to the locked door to open up the path to the Lambda transit system. Shepard's squad comes across several more HECU survivors who are confused as to why the Black Ops are here and attacking them. Adding them to the group, Shepard's squad clear out the Black Ops guarding the transit tracks, and eventually locate the switch that opens the transit system door that leads to the Lambda Sector. Shepard then gets on the tram, and rides it to the locked entrance of the Lambda complex. Getting off the tram, the corporal goes through a nearby vent leading to a very familiar room...
This Chapter contains examples of:
- Ascended Extra: The Black Ops return here, and they serve a much bigger role in the story than they ever did in the original game. For one, they now have a male variant, armed with the same submachine guns and assault rifles used by the HECU. They're also made to be villains towards the HECU as well as the Black Mesa personnel.
- Cavalry Betrayal: The Black Ops end up turning on the HECU, apparently due to the latter's members now being deemed as liabilities.
- Creator Cameo: Two scientists are lying dead near their desks, which carry the name-tags "S. Reardon" and "S. Jones", referencing Gearbox Software developers Sean Reardon and Steven Jones.
- Dark Is Evil: In contrast to the HECU's camouflage pattern uniforms, the Black Ops wear black uniforms. They're also immediately established to be ruthless killers going after any surviving personnel, HECU included.
- The Engineer: You come across another Engineer in the Black Ops controlled hanger who's on the verge of dying, which the Medic that Shepard met just beforehand needs to be brought to him to get healed. After the Medic heals him up, the Engineer is brought over to open up the locked door that leads to the Lambda Sector.
- He Knows Too Much: Apparently, the HECU stragglers left behind in Black Mesa are now considered a liability by their own government, and thus are to be targeted by the Black Ops alongside the surviving Black Mesa personnel.
- Laser-Guided Karma: The HECU as a whole finally get to experience what the Black Mesa Personnel did only a day before, when their supposed allies the Black Ops turn on them too.
- The Medic: First appearance of the Medic as a squadmate. When someone in the squad is heavily damaged, including Shepard, the Medic will walk up to them and heal them back up to 100 health.
- Permanently Missable Content: The optional locked door that leads to a room of supplies can't be accessed if the Engineer squad mate dies early.
- Sidetrack Bonus: At the beginning of the level, there's an optional locked door that the Engineer can open up, which leads to a room of supplies.
- Unique Items: Outside the Boot Camp tutorial, there's only one dedicated PCV charging station (found late in this chapter). All other charging stations are HEV standards. You don't even see the "commercial" charging station also seen only in the Boot Camp level.
- You Have Outlived Your Usefulness: The HECU stragglers left inside of Black Mesa, like the Black Mesa Personnel before them, end up becoming the targets of their own government's soldiers when the Black Ops turn their guns on them.
