Apparently it was done onto the rubber seal that sits almost up against the glass when the door is shut. You can see the workings of the virtually-comatose mind though, in a kitchen thinking it was a bathroom, what's the thing that most resembles a toilet? Aha! This thing has a circular loo-seat thing that opens up to reveal a dark hole... And if the room was spinning enough anyway who's he to argue about whether the whole is facing upwards or not?