Secret & Challenge Achievements

Rescuing Charles: Inspect the files on the whiteboard to find the 'The End (5/8) | Robot Puppets' File. Interact with the large life support device and then the computer, reading all files, especially the diagram for a code. Return to the far left and interact with the chain console control panel. Adjust the lamps by pressing the purple/orange button twice, the yellow/green button once, and the blue button twice to match the computer diagram. This reveals stairs leading down. In the Secret Corridor, examine the courier clothes, then enter the doorway at the far left. In the secret room, examine the diary, then inspect the Beta Type Consciousness Transmission Device for the 'The End (6/8) | The Research Information of Consciousness Transmission Device' File. Speak with Charles, grab the Crowbar from the far right, and use it on the holding cell door to free him. This unlocks the 'The Story of Rescuing the White Mustache' Achievement.

Decision Time: After rescuing Charles, you'll face two questions. The first choice has no impact, but the second choice determines which of two Achievements you unlock. You cannot get both in one playthrough without reloading an earlier save.

Turn it off: Choosing to 'Turn off the equipment' unlocks the 'The Liberation' Achievement and the 'The End (7/8) | The History Between Edward and Luna' File.

Keep it on: Choosing to 'Leave the equipment on' unlocks the 'The Benevolence' Achievement. This choice prevents you from unlocking the aforementioned File.

The Final Confrontation: Regardless of your choice, you will need to return to the secret room where you rescued Charles. Head down the stairs when ready.