The no-man's-land region that I have thought to exist is below the blue line that represents the spine and above the red line that I assume represents a main artery running near the top of the lungs (in the picture). I would think an arrow through the very top extremity of the lung(s), above the main artery would be less lethal than a direct hit through the center of the lungs. I don't think it's too far fetched to think that a deer could live through that if for some reason the bleeding was minimal. The no-man's-land that I have always thought of is most definitely not above the spine. According to that picture, a shot above the spine would be little more than a flesh wound, or a possible broken rib(s).