He wakes up to the smell of damp concrete and the rhythmic scratching of something behind the walls [4, 7]. His only connection to reality is the peephole, through which he watches his neighbor, Eileen, pass by in the hallway, oblivious to his frantic pounding [1, 2, 8].
He realizes too late: the chains weren't kept there to keep people out. They were there to keep the room from leaving. Silent Hill 4: The Room Free Download
Then, a hole appears in his bathroom wall—a jagged, pulsing rift that leads not to the plumbing, but to a series of nightmares [2, 4, 7]. He wakes up to the smell of damp