How does the Big Market work?

Question

In Valerian and the City of a Thousand Planets, Laureline and Valerian go to the Big Market to retrieve a pearl and a "converter animal" (not sure how they are called).

How does this Big Market work? I am obviously looking for some in-universe explanation, not hard (or even soft) science based.

The area of the market is a desert, as seen without the glasses. Once one wears the glasses, another view (dimension?) appears. The inconsistencies I noticed when watching the movie make me wonder how it is actually supposed to work:

• Valerian and Laureline are the only ones visible on the desert, being within the market at the same time.
• They are subject to physical threat both within the market (Valerian is hit, then carries some weights, etc.) and in the desert (where they could just be shot)
• There is a way for objects from the market to move into the "desert world", as seen with the purchases of the two visitors (the human couple), as well as the monster jumping out to attack the bus
• Valerian shoots in the virtual world and falls between "floors" (there are several levels in the virtual world) - how would that match with the desert?
• When in danger, why not just removing the glasses, since he is physically on the desert anyway?

Answer 1

Valerian and Laureline are the only ones visible on the desert, being within the market at the same time

The other mall tourists are also visible on the desert. It's just that Valerian and Laureline moved to a different part of the desert to not attract their attention, so they're never nearby.

They are subject to physical threat both within the market (Valerian is hit, then carries some weights, etc.) and in the desert (where they could just be shot)

Only their physical bodies are ever under physical threat. Valerian, at one point, inserts his hand into a dimensional portal box, where it gets weighed down by the weights, which threatens that specific part of him. But though the portal box and his hologram seem programmed to loosely obey the laws of physics within the other dimension through some unseen technology (i.e., it observes gravity and can do things like 'grab' a rope), his hologram can't be "shot" the way his hand can -- the projectiles pass through.

There is a way for objects from the market to move into the "desert world", as seen with the purchases of the two visitors (the human couple), as well as the monster jumping out to attack the bus

There are several larger 'checkout' portals through which the tourists can transfer large purchases. The organized crime boss alien is seen attaching the monster's cage to one of these, through which it enters the desert.

Valerian shoots in the virtual world and falls between "floors" (there are several levels in the virtual world) - how would that match with the desert?

The shooting is possible because he put his hand through a small portal, specifically for the purpose (it seems) of being able to hold and fire a physical gun in the other dimension. The 'floors' are never really explained, but it seems like the hologram will independently obey the laws of physics in the other dimension when they diverge from what happens to the wearer of the hologram headset. So it's likely at that point Valerian was just laying on the ground of the desert, just like he was likely just jumping up and then standing there holding air when in the other dimension he was swinging on a rope.

When in danger, why not just removing the glasses, since he is physically on the desert anyway?

His hand gets stuck in the portable portal and he can't remove it, so he's in danger of losing it.