Friedkin: This scene presages what's going to come later in the film, when they have another physical altercation that is a lot more disturbing.
He was referring to the original ending of the spiderwalk and the crucifix' scene. As Chris tried to take the crucifix off Regan's hands, she was shouting the same things of those previous scenes: “Regan, stop it… give it, give IT TO ME! “