He walks in the door with the pursuit of haste in his gift bag, something from the Lego store. A last minute but expensive for the gift drive. Heels down past carpet onto tile floor, tux and scarf, half way down toward the elevator in the core of the building, he turns around. He could be at the wrong party venue, on the wrong night, one location amongst dozens across the city. Or he could be in the right place and just noticed the mirrors leaning against the brick, ancient and vintage rusting or however it is that old glass and reflection ages. He examines himself, bow tie, bag, hair, then turns back.
Right, I realized, moving past the judgement of vanities and landing in that empathetic point of self-interest. If you put a mirror in a hallway, people will use it. Maybe not before sunset, but certainly after sunrise.