Tia - Not that I want to defend Fox, but what you saw on NBC was not the Fox pool feed.   My understanding is that Fox was responsible for providing a pool feed which is cut by a director and did not feature the side by side shots, as designated by the debate committee. I believe that C-SPAN would have used this feed. The individiual cameras were also made available to the networks, but they basically "take at risk". They could not be sure when the operator would adjust the shot.

Having worked in control rooms, I can tell you that each cameras is operated by individuals - the camera operator set up their camera shots to prepare for the director to take their shot.   Once the shot is ready, if the director likes the angle, the director will call for the technical director to take the camera. Since it is a live event, the cameras will shift to adjust for the subjects movements.

What NBC, and other networks, were doing was creating their own broadcast from the available cameras. Not having direct control of the camera operator, they had to do the best they could.