Decontamination Chamber

Follow the coned path to a bunker and enter. Use the airlock terminal by pressing the button and scanning the security monitor with your Interface Module.

Enter the elevator and press the up arrow to reach the botany lab. Use your security access to enter the Main Wing.

Proceed to Laboratory 01, use your Interface Module to unlock the door. Listen to the voice recording and read the terminal. Crawl through the vent behind the terminal.

In the vent, follow the path to a water cistern area. Save at the Wireless Access Point. Crawl underneath the gap in the door to the right.

Locate the keycard on the table in the center of the room and note the name and number. This area is no longer safe; the entity will now roam.

Go to the terminal marked 'Maria's' and enter the code from the keycard (e.g., 9785). Press the 'EXE' option and follow the cables through the now-open door.

Go past the Lab 02 room and into the dark hallway. Crawl into the vent at the very end.

Follow the vent path to the chemical lab. Save at the access point above the hatch.

Interact with the terminal to mix chemicals for the decontamination scan. Use the notes in the room to find the correct combination: Base: Isopropyl Alcohol, Active 01: Copper Ions, Active 02: Hydrogen Peroxide, Stabilizer: EDTA. Press 'TEST'.

Backtrack to the lobby area where you first entered. Enter the decontamination chamber; the disinfectant will be applied automatically.

Enter the chamber and pick up the keycard on the floor beside the body.

Return to the area with Maria's keycard and terminal. Enter the code from William's keycard (e.g., 4619) into the terminal. The gate to your right will open.

Climb down the ladder, follow the hallway, and climb down a second ladder. Navigate the dark area by following the red pipes and objects on the ceiling.

Reach the crank wheel and press E/M1 to turn it.

Make your way back through the tunnels to the ladder. After the cutscene, climb up the ladder.

Run to the cafeteria area and crawl under the door to reach the cistern. Climb down the ladder.

Follow the tunnel and climb up another ladder. Crawl through the vent door into the office.

Inspect the terminal and enter William's code again (e.g., 4619). Go to the 'SECURITY' tab and scan the screen to upgrade your Interface Module.

Make your way back to the lobby, get in the elevator, and use the airlock to return to the Moon's surface.

Go back to the other bunker and use the airlock to re-enter the building, transitioning to Chapter 6.