After riding the elevator back up to the prototype teleporter lab, Calhoun is greeted by a thankful Dr. Rosenberg, who informs the former that they've already put the newly charged power cell into the old portal machine. Walter and Simmons are seen working the power machine to secure the charged cell. Rosenberg then explains that he will need Calhoun's help for the next step of the plan as the two of them return to the main portal chamber. As Rosenberg works the computers to get the chamber up and running, he explains that Calhoun will have to be the one who turns on the power, and to be the one who releases the displacer damping locks each time the portal chamber has amassed enough energy to create a one man teleporter.
Calhoun climbs up to the damping lock control room and flips the switch to turn on the power. He then waits on standby for Rosenberg to fully activate the portal chamber. The coolant line for the portal chamber ruptures midway through activation, which Calhoun has to turn a valve to release the pressure as Xen creatures start to teleport into the lab to attack him. Once the problem with the coolant line is fixed, Calhoun returns to the control room. The chamber eventually gathers enough energy to create a teleporter. Calhoun presses the button to release the damping lock, which creates a teleporter for Walter to go through. The portal chamber then resets, which Rosenberg works to build up the next teleporter. At this point, the HECU can be heard talking in the distance closing in on the location of the prototype teleporter lab. Once the chamber's reached max energy again, Calhoun releases the damping lock to create the next teleporter. This time for Simmons to go through.
Charging up the portal chamber again, Rosenberg states that he will be the next to go through, but informs Calhoun that he's set the chamber to automatically start up again to build up enough energy for Calhoun's teleport. As the energy reaches max, the HECU can be heard banging on the nearby locked door trying to break in. Calhoun releases the damping lock once more to create the teleporter for Rosenberg. As Rosenberg goes through, he wishes Calhoun good luck and that he will see him on the other side. Left alone in the prototype teleporter lab, the HECU succeed in breaking in, and attempt to attack Calhoun. Once the automated chamber builds up to full energy again, Calhoun releases the damping lock to make his teleporter. He then fights through the HECU soldiers that have invaded the lab, and escapes through said teleporter.
This Chapter contains examples of:
- Anti-Climax: For being the last time you fight enemies, there's not much of a final battle, or even a Boss Battle like what the original Half-Life and Opposing Force had. However, it's somewhat justified in that the goal for Calhoun and company is to just escape the facility.
- Final Battle: In a way, this serves as the final battle as Calhoun, Rosenberg, Walter, and Simmons work to escape the Black Mesa facility. Though the battle isn't all that tough. Just a couple Houndeyes that teleport in while fixing the coolant pipe problem, and a few last minute HECU soldiers that can be easily avoided by just running for the teleporter.
