Can you explain to us the shot in which Eric shots in his hand?
Well, in terms of visual effects I can. For motivation you’ll have to talk to Mr. Cronenberg. Apparently Robert Pattinson and his handlers balked at the thought of doing this as a practical effect so he just pointed the (unloaded) gun at his hand and pulled the trigger. We added the muzzle flash, smoke, wound and blood splatter in compositing.
They explain much more in their piece, it's definitely a must read for fans! - plus check out some of their work below (more in the article).