In the Series II the episode "Parallel Universe", Lister, Rimmer, and Cat board a parallel universe Red Dwarf. They are seen exiting a small room labelled "Air Lock" that looks identical to the stasis pod that Lister originally was in. The sign on the wall is labelled LEVEL NIVELO 413 which seems to be a common level/floor on Red Dwarf being that it has been seen/reused in other episodes. It is also, coincidentally, a number which recurs in the webcomic Homestuck commonly.