I had a parallel world experience yesterday.
I went to pick up my son after school. I walked into his section of classes. After looking everywhere, noting that they had done a little re-decorating since the morning, I couldn’t find him, so I asked a teacher. She mumbled something in Swedish, which I took to mean he was probably playing outside, so I thanked her and said I’d check out there. On the way out, I noticed they took my son’s nametag off his locker and replaced it with another student’s name.
I walked outside and couldn’t find my son anywhere. That’s when I realized, I hadn’t been on the right floor.