The puzzle in Thomas’ office in The Medium can be a tricky one to solve. It requires you to use all of Marianne’s abilities to work out how to progress to the next area, but it might not be clear to you what some steps in the process are. You will come across this puzzle after you catch up with Sadness on the second floor. After that cutscene, head into Thomas’ office.
Notice the grandfather clock on your left as this is important for this puzzle. Head behind the broken desk. Interact with it to grab a flashlight and the grandfather clock key.
Walk to the clock and use the key to gain access to the clock dial. Start spinning the clock’s hands using the left thumbstick on your controller. This will begin to alter what the spirit world looks like and allows you to see different Memory Shards of Thomas. You can stop to listen to what he is saying by interacting with the Memory Shards. If you don’t care, though, spin the hands until you approach the five o’clock position.
You will see a secret passageway open up in the spirit world, which Marianne will comment on. Ignore that for now and continue spinning the hands until you reach four o’clock. End your interaction with the clock and head back to the desk.
A Spirit Well will be present in the spirit realm. Refill your energy meter and go back to the clock. Spin the hands again until you see the secret passageway. Marianne can’t access this in the real world, so press the B button to activate her Out of Body Experience ability.
Head through the secret doorway and use your Spirit Blast on the power generator in the hidden room. Return to Marianne’s body and interact with a cabinet, in the real world, where the secret passageway is in the spirit realm.
You can inspect a framed photograph in this cabinet for more backstory. However, if you use Marianne’s Insight ability by pressing the left bumper button, you will see a hidden button mechanism behind it. Move the photograph and push the button to move the cabinet. Marianne can now pass into the secret room in both worlds and progress to the next area.