@nobodygattaknow
Their apartments are opposite each other. The panel where he places little Bomei (the dog) down, his back is facing his apartment with the door being open. And he's looking at the FL's apartment door.
About whether he knows her personally.... that's part of the mystery you'll...
@kaori19 I'm wondering about this too, but I'm pretty sure there's some reason for it since the summary mentioned hidden secrets of Abella. Stay tuned and we'll see ^^