He heard the unmistakable sound when he opened the door. The aliens shoes, occupying the space normally reserved for his, made him certain. Unthinking, he shut the door, retreated back down the lonely hall, finally taking refuge in the elevator. He was benumbed as he descended, arriving on the first floor with a shudder running through his body just as the elevator ground to a halt.
He had suspected for some time. Hearing the confirmation was more than he could take.
When he stepped out into the cold, January weather he was shocked by how it contrasted with the steamy apartment.