Upon entering Room 810, the player will find a two-story Victorian-styled mansion, Specimen 12 itself. According to the notes scattered about, there is a commotion going on below the kitchen. There are also hints of what seems to be a man chasing after the note writer.
The mansion consists of a wine cellar, a parlor, a dining hall with a fireplace, two hallways, a library, and two bedrooms, all of which can be explored by the player. Once the player hears The Old Man, they must hide using the local objects, otherwise he will quickly sprint towards the player, instantly killing them. The player will eventually find the fake book in the parlor. Using it on a bookcase in the library reveals a trapdoor to the underground room, where the exit room key can be found. After escaping the room where the key is acquired, The Old Man continues to chase the player like another Specimen.