The Real World Interface or RWI connects the outer shell of the TARDIS and its internal architecture. In a normal TARDIS this would appear as a black void when the TARDIS doors opened, that would dissipate when stepped across it, maintaining the illusion of the TARDIS and its outer shell being the same size. Alternatively, the doors themselves are sometimes designed to function as the RWI, although anyone opening them will see a seemingly impossibly space inside when they do.

The Justice Station works a little differently, with the TARDIS interior intersecting with the ship’s exterior at multiple locations. Each courtroom is part of the TARDIS interior, as are each set of quarters and the engine room. Everywhere else, including every area where prisoners are detained, is part of the exterior and each RWI is completely sealable. Getting through a set of these doors requires advanced technology of at least TL 7, and, given that each renegade is searched the moment they arrive, that’s very unlikely to happen.

But not impossible. After all, Time Lords are ingenious and all it takes is one sympathetic guard…