Why would there be a secret (which would be a trigger area placed there on purpose) that cannot be accessed? Is the implication here that it was dropped into the map by accident due to someone misclicking?
Sounds to me like trolling. Pressumably they were using the map editor to make warp zones and trigger areas and discovered this impish creation by combining the two. I doubt Romero knew about this trick but I can imagine he left the question open whether ever a way could be found. Such things may not be obvious even to the programmer of the game.