He was moving up the second flight, into the semi-darkness, slowly and wearily. He paused and listened, glancing upward; there was no sound and all he could see was the dim shape of the projection of the wall at the next landing and a corner of the door opposite—the rear door, which was rarely used.
Involuntarily—a habitual gesture performed without awareness—his left hand went into his trousers pocket and came out holding a ring with two keys on it, and still involuntarily his fingers selected one of the keys and turned it to the correct position for insertion in the keyhole. His right hand remained tight on the rail, as if without that support equilibrium would desert him and he would tumble backward like a puppet severed from its string.
He felt the key in his hand and looked down at it, wondering how it had got there.