He steps out into a world through the mirror. What world he knows not, but he senses that he is not on the shadow Earth he grew up on.
When he turns around he sees himself reflected in a rectangular mirror hanging slightly crooked over a cracked bathroom sink in a small powder room. The door to the bathroom is closed. He does not hear any sound other than the erratic and lonely drip of water leaking from the slightly rusty spigot in front of him.
While the bathroom appears old it is actually quite clean other than a bit of dust here and there. It probably hasn't been used in a while.