"We were pretty sure that was going to be controversial. It's not like we were deluding ourselves, and we weren't just doing it to be cool. We felt, in the case of Zod, we wanted to put the character in an impossible situation and make an impossible choice. This is one area, and I've written comic books as well and this is where I disagree with some of my fellow comic book writers - 'Superman doesn't kill'. It's a rule that exists outside of the narrative and I just don't believe in rules like that. I believe when you're writing film or television, you can't rely on a crutch or rule that exists outside of the narrative of the film. Also our movie was in a way Superman Begins, he's not really Superman until the end of the film. We wanted him to have had that experience of having taken a life and carry that through onto the next films. Because he's Superman and because people idolise him he will have to hold himself to a higher standard."