The series was a hoax at the expense of its contestants, who were told they were being trained as cosmonauts at a Russian military base before undergoing a five-day trip into low Earth orbit. In reality, the entire series was filmed in Dore, and the contestants did not leave Earth.
Gravity at the height of the ISS is still about 90%. It’s only being in orbit that results in free-fall giving a zero-g effect, not so different from those “vomit-comet” flights.
So if they’d come up with some explanation about it staying up without being at orbital speed it would have been closer to the truth.