When you're working with film, you can only shoot one angle...

When you're working with film, you can only shoot one angle at a time, and then everything has to stop, and you re-light it and shoot everything else from the opposite side, so it's really important that you stick exactly to what's written. But with the multi-camera digital setup, you're getting both sides of the scene at the same time, so it gives you that freedom to go off-book.