To die from having all of your blood extracted? In this situation, someone is tied to a chair and having pint after pint of blood drained from them using a syringe multiple times. I know they'd feel the puncture of the needle, but wouldn't they just pass out after a while and...well, die? It seems like a less painful method to me since they'd be unconscious during the actual time of death, but I could very well be overlooking something.