Completely in shock
As soon as Sebastian entered the room, he was shocked by what he saw. He needed a moment to gather his thoughts and relax. To make sure he was where he was supposed to be, he took another peek behind him. That explains why the girl wasn’t grinning and waving from her window.
Not a single speck of dirt
The space was empty. No indication that someone has lived there recently could be found. The only oddity was how spotlessly clean it was—Sebastian couldn’t discover a single particle of dust or dirt. Why had that happened? Sebastian frantically combed through the other rooms in quest of a hint.