You try to do as much as you can on set because practical looks cool and practical looks great. Until you get to a point where the reality is you look at it - and I went through this in my last movie which was a war film, which my brother fought in Iraq and I did a ton of research and as much as I could made it documentary-like - and then at some point on set, the reality is somebody says to you, "You know, you can use a real squib and you can have three hours of clean up and you can lose five shots or we can do that blood explosion in post and you can get those five extra shots."