"I think the beauty of documentary work is that it's a mystery - you never know where it's going to lead you. You start out with some notion of it, but it's very different from a script. A script you write, you shoot against, and you know what the story is going to be. There's always the element of surprise, but the surprise comes from performance, from something that's improvised, it comes from someone who sees it inside an already determined framework. In documentary, it's never determined. It's never the same, and affords enormous possibility."