Interesting thought about a possible escape route from the entity's realm

So we all know the lovable demogorgon, with his unique powers and being probably the second most fun killer to play as and against (first being GF). I was thinking, "Why doesn't the upside down look the same in DBD? And how does the Demo manage to travel so fast in the upside down?" After a bit of time thinking on it I've come up with a way it could possibly be (or part of) an escape route from the entity's realm, with a few assumptions:

1. The upside down is the actual upside down, and not some emulation of it.
2. We (the players) view the game through the eyes of the entity (which in turn is viewing through the eyes of the killer we control). We'll also assume this implies that killers cannot see auras, but this information is being fed to them by the entity.

With that out of the way, let me show my theory.

First, lets answer the questions I said above.

"Why doesn't the upside down look the same in DBD?"

This was the initial question that started the theory. It was hard to find much reason at all (outside of 'not wanting to program it'), but I think I have a plausable reason why. The upside down is not part of the entities subrealms, and possibly exists outside of it. Whenever the demogorgon enters a portal, the connection between it and the demogorgon is severed, which explains the moments of "undetectable" the demogorgon gets afterwards as connection is re-established. The entity cannot see, causing the blackness, but can still sense auras which the info of them is fed to the demogorgon after exiting. The red light is the entity's "stain" reflecting back as connection starts to become re-established as the demogorgon exits the upside down.

TL;DR: The upside down is the same upside down we know of from Stranger Things, the entity simply cannot percieve it since it's not it's realm.

"How does the Demo manage to travel so fast in the upside down?"

This ties into the first question and how the upside down does not exist within the entity's realms and exists outside it. Time in the entity's realm is meaningless. It's able to pluck from whatever time period in any order it wants. The upside down shows that to an extent when the demo uses it; the time in the entity's realm is slower than in the upside down. Thus, when the demo travels using it, it moves at (comparibly) amazing speeds.

"How could the Demo be used to escape the entity's realm?"

This could be used (assuming my first 2 questions and answers are correct) to escape the entity's realm, at least temporarily if for some reason a survivor manages to use the portal or is pulled through by the demo, ending up in the upside down. Outside of the entity's area of control, another weakness could be found or exploited (eg. being that perhaps (and this is pure speculation) the entirety of the upside down is connected in some way, allowing one to travel to a Terra world as long as they could find it, and again a/the demogorgon opens a portal.) Only problem could be that it'd just end up a jump from one realm (the entity's) to the next (the mind flayer) with no real way to escape. Even if Vigo or the Observer manage to execute it somehow and live, the upside down most likely won't work on the same mechanics of the Entity's; no Auric cells to manipulate, and little/no way to study the realms inner workings.