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Chapter 5: Lost
The Callisto Protocol

Chapter 5: Lost

Navigate the treacherous corridors of Chapter 5: Lost in The Callisto Protocol. This guide details how to find Mahler's lab, locate a crucial fuse, and reset the active console to progress.

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Chapter 5: Lost

Navigate the treacherous corridors of Chapter 5: Lost in The Callisto Protocol. This guide details how to find Mahler's lab, locate a crucial fuse, and reset the active console to progress.

Walkthrough
  1. 1
    As soon as you gain control, fend off two infected. Loot the nurse station for goodies and ammo.
  2. 2
    Proceed into the 'Psych Block 1 A320' hallway. Shoot the 12 crawling exploding enemies as they approach. Find an Energy Converter in the first side-path.
  3. 3
    After the second bed, another crawling exploder appears. Clear the hallway, checking cells for ammo and a stompable crate.
  4. 4
    Around the next corner, an Infected and a crawling exploder will attack. Deal with the exploder first.
  5. 5
    Grab the Health Injector at the end of the hallway. A Spitter will drop down after you open the next door.
  6. 6
    Take the elevator down. Exit and grab the Schematic – Tactical Pistol from a barrel.
  7. 7
    Locate the locked door and inactive fuse box. Follow the path to a lab room. Loot lockers and proceed.
  8. 8
    Find a Decoder on a counter between medical beds.
  9. 9
    Continue, noting spikes on the wall. Hop over a barricade, stomp a playing-dead Infected, and loot glass cases. Find the Gate Fuse opposite the second glass case.
  10. 10
    Upon grabbing the fuse, multiple Infected will awaken. Backtrack, using the spike wall and GRP to your advantage.
  11. 11
    Use the fan to kill two Infected. Defeat the final pair near the entrance and backtrack to the fuse box to open the door.
  12. 12
    Grab the Loot Chest in the dead-end room with flaming debris.
  13. 13
    Follow the path to a room with a suspended corpse. Loot tables on the far left. Enter the next door.
  14. 14
    Locate the console with the green lock panel. Find a Pristine Energy Converter in the center of the room. Enter the door beyond the console for a Health Injector and a loot crate.
  15. 15
    Interact with the console and align the red lights on the dials to green. This opens the door. (Solving in under 7 seconds unlocks the 'Quick Pick' Achievement/Trophy).
  16. 16
    Proceed through the burning hallway to Mahler's Lab. Grab Data Drive 1 from the center tray.
  17. 17
    Exit Mahler's Lab through the far door. Find a Skunk Gun Schematic and another lootable.
  18. 18
    Descend through a hole in the wall into the 'Holding Cells'. Loot a crate in a half-open door.
  19. 19
    Enter 'Security Access 1B'. Use a Shiv to open the door and climb the stairs to a Reforge Station. Upgrade your Stun Baton and GRP.
  20. 20
    Enter 'Shower Observation'. Note the debris and crawlspace leading to a hole in the floor. Loot tables and a stompable crate. Avoid the locker in the back right corner.
  21. 21
    Take the crawlspace and drop down. A scene introduces a Biobot. Avoid it.
  22. 22
    Follow the Biobot into the second room. Grab the CPU Printer if you dare. Head into the vent to continue.
Tips
  • Utilize environmental hazards like spike walls and fans to eliminate enemies efficiently.
  • The Biobot is a formidable enemy; it's best to avoid direct confrontation by sneaking past it.
  • The Reforge Station is a good place to upgrade your weapons and sell unwanted items.
  • Pay attention to the security lock puzzle; solving it quickly can yield an achievement.

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