Phantasy Star: Fringes of Algo

Hey guys!

One of the many unanswered questions related to Phantasy Star III I asked myself dealt with Aridia. Well, not really with Aridia itself, to be honest: At some point in the game (Nial's, Sean's or Crys' quest) we get some cool new gadgets for our trusty walking tank listening to the name Wren. Later we find a secret underwater passage. With his new upgrade, Wren transforms himself into a submersible like only Optimus Prime and friends could do. Finally we realize: beneath Aridia lies a hidden world which is home to Laya's little sister.

Now my question is: How exactly is Laya's tiny world included into dome of Aridia?

Is the whirlpool more or less a wet elevator which just leads us down to the basement of the desert-dome?

Or: Could Layas's world actually be upside down, like the second page of a sheet of paper? Of course in this case the gravitation on this particular place of Alisa III has to work in a different way than in the rest of the ship. An upside down world would be one explanation why Wren was able to dive into the water and reappear on another surface in the "lower floors", assuming the passage was a straight pipeline.

Personally, I think it would be really cool if Laya's home was upside down. I don't know if the game mentions whether there was a sky in this secret place or not. Ok, the water is blue and this could suggest the reflection of the sky. But on the other hand, PS III isn't always consistent inthe matter of water (in Frigidia the water is frozen but as soon as you visit Skyhaven it magically thawed, for example).

But: Whenever you see the Alisa III you also see that the lower half of the ship consists of metal (?) domes while the upper domes are made of some kind of glass (?). So: No sky in Laya's world? Or are they using artificial sunlight in this place?

Or: Is the dome under Aridia really fully surrounded by metal? Maybe there is be a large window in the metal structure allowing them to have a nice view of the sky. I mean, as far as I remember there is no artwork or in game graphic which shows us the complete bottom of the Alisa III So there might be room for speculation And Laya's "dome" appears to be significantly smaller than Aridia so a large window should be enough.

And one final thought: Is Laya's world the reason that Aridia is a desert world? It always puzzled me why anyone should create a large of a spaceship only made of rocks and sand. Especially since the ship's purpose was to ensure the survival of its people. It doesn't make any sense to me to place a hostile desert on an ark.
Unless: Laya's world needs too much water and other resources so Aridia came up short. Remember, the hidden land seems to be rather fertile and rich of water. And of course it uses a lot of space under Aridia. Room which could have been used for systems and machines to support life and a more friendly environment in Aridia (pretty selfish of Laya and those creepy old guys who stare at her while she is sleeping ). But I am getting ahead of myself.

So what do you think? Is Laya's world upside down? Or is it a lower level? Or do you have other suggestions?

Can you use the monitor within that world within a world under Aridia? I dont recall. But if it was another dome, it would surely show on the monitor, correct?

The dungeons that connect the domes or just exist period often show stairs that lead "up" when you enter/exit, give the impression that under each dome is indeed just a more metal/mechanical architecture.
Perhaps the world within a world under Aridia is more akin to a greenhouse, or even akin to the classical trope of how people imagine Atlantis under water. Not exactly a dome proper like the rest, but still a synthetic environment as opposed to metal/mechanical. After all, in the regular domes that are well lit, I would guess that they have artificial sunlight, as Alisa III doesnt rotate like a planet or moon. So the world under Aridia could just utilize more of that synthetic sunlight and greenery.