Third Door Revisited
A lot of the setting has changed since Out of Key has started. For instance, on the first page, this door has a window. But I imagine the room was previously used for storage and the maintenance crew didn't really want kids to peek in at the chemicals and supplies that could be potentially stolen or messed with.
Look at the Chapter 5 Teal. It's only been a couple days in comic time, but she's changed a lot since the beginning of the week.