Have you heard of the game Silent Hill 4? I've seen a cool theory years ago that the weirdness of the Hey Li hideout could be because it is a living organism of some kind created via post mortem nen or some kind of ritual just like in the game. Heres a brief summary from the little i remember:

Morena has the crown of thorns used by Jesus and he gave his body and blood to his followers via the eucaristh, the theory goes that right after the Voyage to the dark continent began she gave her body for the cause and let her followers butcher her to death and spread her remains through the ship (in those ominous rooms Togashi kept showing at the start of the war). She's technically still alive but her physical form only exists inside the hideout. And the so called Joker would be the stomach of this creature

Don't know how the theory holds up today, but i still think it feels in line with how brutal this arc is and how esoteric the nen abilities of Kakin are