I hope gitana is right. I've often thought that we humans are different from many species in that we are cursed with the knowledge of the inevitability of our deaths. I could find some comfort in the notion that in this kind of situation, people might be blessed with a sense of calm. I have read that in that kind of severe incident, the body is flooded not only with adrenalin, but some other chemical (which now escapes me), which attaches to the opiate receptors in our bodies, producing similar effects of those drugs.
A close friend of a close friend of mine was stabbed multiple times by a crazed ex of his fiancee. He told my friend that he was so enveloped with a sense of calm, of peace, of pain free euphoria that he actually considered just lying on the floor and enjoying the sensations which were flooding his body. Meanwhile, his assailant was calmly getting cleaned up in his victim's shower! Finally, the friend thought of how upset his fiancee would be if he died, so he dragged himself to the phone and called 911. Fortunately he survived. I had completely forgotten about this guy until I read gitana's post, which I confess at first reading I completely rejected.