My A-number one visceral fear is speed. More than knives or snakes or confined spaces. Speed. I won't even go on a motor boat if I can help it.
You have to really make sure that every moment means something, and that every moment, there's a purpose for it. And then you have to blend it all together without it looking like you're really focusing on it. That, to me, was the magic trick that was most difficult for the film [Buried].