I’m dying to know the reason but can’t watch the full doc

The shot called for that hamster to be spinning in its wheel, but the animal refused to cooperate at first. Gilliam, a well-known perfectionist, insisted the shot work exactly as he envisioned it, and the crew spent the rest of the day trying to get it right, succeeding several hours later. This meticulous approach was nicknamed “The Hamster Factor” by the crew for the remainder of the film’s shoot.