Amnesia: The Dark Descent/Archives

The archives is a safe map. At most, you may have some sanity loss, but it is not much of an issue. The objective in this map is to retrieve the Wine Cellar key.

Head forward and to the right. Go to the end of the corridor, and walk past the fallen rocks. Enter the first room on the right, and pickup a loose rock on the ground. Throw it at the hole on the wall leading to the library room.

In the library room, move the three switch-books on the shelves to unlock the study. They are visible if you're looking in the direction of the wall containing the hole. The first book is on the shelf next to the hole, and two more are on the middle shelves. Pulling all three switches will open the study, where you can get the key.

Picking up the key will have the exit door smashed open. You can now return to the entrance, although you will see a monster going through the door you need to exit.