Stephenie Meyer Addresses 'Breaking Dawn - Part 2' Ending

The question, which I got frequently, was how I felt about having a big change inserted into the story during the final climax. My answer was that it didn't feel like such a huge departure. For me, this moment is already in the book. However, we don't get to see it in all its exciting and gory detail because we are seeing the world only through Bella's eyes. A few of the reporters I talked to wanted to know where in the book this moment was hidden. The answer is page 738, fourth paragraph down:

"Aro stared into my eyes for a long, tense moment. I had no idea what he was searching for, or what he found, but after he had measured me for that moment, something in his face changed, a faint shift in the set of his mouth and eyes, and I knew that Aro had made his decision."

In this short analysis, after Bella has revealed the depth of her power, Aro plays out in his head the probable outcome of a battle with the Cullens. Much like what we see in the movie, Aro foresees a more evenly matched fight than he had expected, the loss of too many of his key players, and—most unacceptable—the likelihood of his own death. Though odds are that the Volturi would have come out on top in the end, Aro wouldn't have lived to see it and the unassailable nature of the Volturi's authority would have been broken, possibly forever. It is this vision of the future—though imperfect guesswork on his part—that motivates his retreat.

Melissa Rosenberg and I have both mentioned the fateful dinner we had (back during the filming of Eclipse) where we hashed out a way to make the end of Breaking Dawn more cinematic. This was the idea we latched on to—how do we make this vision of Aro's into something the viewer can experience? The answer was pretty simple once we looked at it that way—we already had a character who could show us visions. So the only real change to the book ending of Breaking Dawn is that Alice enters the scene earlier, and comes in contact with Aro.

(Are there a few little trespasses against the mythology in this vision? Yes, as some of you have pointed out. The consensus was that a minor deviation from what had been established was forgivable in the name of entertainment. I had a few very elaborate solutions, but they were too confusing and not nearly as cinematic as the final product. And obviously, the result was very entertaining.)