No one in particular. Probably just some random shmuck so I can **censor** with them.
I'd have the door open already, greet them before they can process what just happened, apologise preemptively for interrupting anything important they were doing then I would shut the door without saying goodbye. Whatever happens from there I'd just improvise.
If you were to pick a Tarot card that matches your personality, which would it be? Be honest, don't just pick the nicest one, pick the one that is most accurate. Why? Cuz it's fun.