That connecting chamber was simply a "duct" that allowed more CO2 to dissipate into the air, as the chemicals in the Great Pyramid combined and gave off excess gasses due to chemical reactions.
As the Fallen Angels, that ran the Great Pyramid, would pour their different elements into the internal chambers of the GP, the resulting by product was pure, unadulterated, electricity. It would then be focused, and released, traveling the massive Obelisks outside of the Pyramid, until it could be harnessed and used to power the Fallen Angels massive palaces of gold.
This way, when they invited their Nephilim children over for dinner, they didn't have to sit in the dark, while eating. Also, their human wives, taken from the daughters of men, could use the electric so they could see in the dark, which was very handy when putting eye make up on at night.
This art of painting their eyes was taught to them by one of the Fallen Angels, just read the Book of Enoch, and Book of Jubilees.
You see, that's what Russel did, and that's how he came up with a bunch of Looney ideas concerning the Pyramids.
By the way, all of the above is SARCASM , lol. It just sounded like something Russel would have said, and I wanted to share his "knowledge" with you all, lol.