I agree there is no "void,' what I mean is that there is a place in which you can put an arrow through on or both lungs, and still not retrieve the deer. And yes I know the bubbly blood thing. Asfor the pneumothorax causing death, not always, as I've seen in many humans. Also, often times our SHARP broadheads make nice little "flaps" when they pass through tissue, which in turn can act as valves, allowing air to enter AND escape the chest, somewhat equalizing the pneumothorax. Also the fat tissue and the thick skin of a deer makes it a little more difficult that it would be in you or I to develop a severe pneumothorax. I agree that most deer shot in this area probably will/and do die, but I've known of quite a few that didn't, but as I said, that is probably not the norm. The deer in this pic would have had me concerned had I not heard her go down, and know the angle of the shot.