u/Potential_Yam_9821

In the few Kane Pixel YouTube videos I've watched, we learn that the Backrooms were created by the company A-sync due to an experiment that went wrong, or perhaps not.
So I think the MRI research is just a pretext to advance research into the Backrooms without it becoming public.
Even though the Backrooms can distort space and time, we have proof that A-sync was there before Clark, since the first scene shows an A-sync agent dropping off a bag that Clark later retrieves through a hatch. On top of that, there are several A-sync agent suits in the room with all the clothing in the basement.
Knowing that A-sync wanted to make this place habitable, I think Clark may have discovered the site of the experiment's incident (since a lot of furniture is concentrated near the entrance to the Backrooms door in Clark's store, and becomes increasingly sparse the further you go), or at least an entrance to the Backrooms, hence the scene where the A-sync boss seems quite surprised to see him on one of the installed cameras and tries to track him down, which is further proof they were there first since a camera had already been installed.
A-sync then wanted to eliminate him to prevent any information about the place from leaking out. While all the creatures seen in the Backrooms section of the film are harmless (meaning they are purely appearance, as shown when Clark takes a bite out of one of the creatures during the meal, they feel nothing and don't bleed, which I'll explain later), the Captain Clark monster is the only one that bleeds during the fight with Mary. I assume it's a kind of creature/monster that A-sync sent to erase the evidence Clark had gathered such as the moment an entity steals Bobby's camera (which I assume is Captain Clark). Also, Mary comes across the mural depicting Captain Clark lifting a person toward a window. I think the mural was made by Clark with Captain Clark's help (hence the height of it), and that it depicts Clark himself at the moment he realizes he prefers to stay in the Backrooms, represented through the metaphor of Mary as the window of freedom. All the other elements are things Clark discovered about the Backrooms (the levels, the yellow suits, etc.). In my view, this mural illustrates the bond between Clark and Captain Clark, and that this creature is the sole reason Clark stays in the Backrooms. Captain Clark would therefore have manipulated Clark to the point of even killing his own friends (Kat and Bobby).
Finally, after Mary arrives in the Backrooms, long after Clark, due to the Backrooms' time distortion, the monster wanted to eliminate them both, fearing that Mary might bring Clark back to his senses and that information damaging to A-sync might leak into the real world. What supports my theory is that Captain Clark appears during the meal, right when Clark seems to have done some inner work on himself. A-sync therefore first killed Clark, then trapped Mary using gas deployed via a decoy at the center of the replica of Clark's store, knocking her unconscious (it's clearly A-sync, since the same signs can be seen in their laboratory at the end). Finally, the ending scene shows Mary arriving in the A-sync laboratory, with Captain Clark in one of the lab's rooms, which, in my view, confirms my theory. Mary seems to have understood what was going on, as she asks where she is and whether she could regain her freedom, which would logically be a yes since she did nothing wrong.
One more element I'm not sure where to place: the A-sync "MRIs" might be there to distinguish humans from creatures.
The Backrooms would therefore only replicate traumatic scenes from reality, for example, the ending scene showing Mary as a still-life in the A-sync lab room, most likely reminding her of her traumatic childhood due to her isolation and hospital visits.
As for the meaning of the Backrooms, it would ultimately be a place representing people's trauma tied to loneliness, shown through the appearance of Clark's store or Mary's childhood home within the Backrooms. Moreover, this loneliness stems from a rupture, both symbolic and concrete (Clark's broken glass = Clark's separation from his wife; the broken handprint = Mary's memory of her mother). Thus, the small number of creatures present, who also don't speak, and the various elements tied to what made a person lonely (the furniture for Clark, Mary's psychology book stand) would be a way of eternally representing these traumas, hence the soulless creature that takes the victim's place, the still-lifes, and therefore the reason these creatures have no interior. Furthermore, the only known characters with a still-life are Clark and Mary, whereas Bobby and Kat do not have one because they are not alone.
The Backrooms would therefore be a way of gathering and making familiar all of these traumas, which is notably the purpose of liminal spaces — that is, to make frightening places that evoke loneliness feel familiar.
Sorry if I'm repeating things that have already been said or that are obvious.
The more I re-read my theory, the more I feel like nothing holds together, but I'd be curious to hear your thoughts, especially if any elements are contradictory or simply wrong.
Thank you very much