I think the reason there was no blood is because its a survival mechanism of the body. I have read of and heard of people who lose there arm in a quick many (such as in the vid) and the blood vessels constrict because the arm is by all standards "non-vital" which stops them from bleeding to death....the body knows how to survive.....
It doesn't work like that though, not when you have a whole fucking arm missing. It's a fake video.