I am having a hard time correlating what I see in the Wiki and what I'm seeing in the game itself.
According to the wiki...
Sometimes closets are generated without doors leading to them. The only way to get to these is for a corridor to be generated adjacent to them, or to teleport or dig in. Such closets always have a scroll of teleportation inside, and a potion of object detection will reveal its presence. Every closet has either a door or a scroll of teleportation.
However, I have come across many, many closets, and I have never seen anything inside them. At one point I teleported to the vault, but that was just on a random pathway. Am I missing something?