All shows (including ours) sometimes use two cameras (referred to as
the A and B cameras). Adding a second camera costs money, because you
now also need a second camera operator to run it, second focus pullers,
dolly guys, on and on. In general, all of your main footage (masters,
close-ups and the rest) are always shot with the A camera *anyway*, with
the B camera usually used for group reactions or coverage in action scenes.