Let's take another example like say: Saruman from the Extended Edition of LotR:RotK. He is stabbed repeatedly in the back, falls downs 5,000 feet and gets skewered on a spiked wheel. To be quite frank the stabs alone would kill him. Why? Just one stab to the back of the chest will severly wound someone. Two will definately kill them. Three he's already dead. Same basic thing: stabbing the heart is just as fatal as hacking the neck, he would've died on the first blow.