I can't tell you how many reports I've heard of gun shots to that area that resulted in the animal dropping to the ground instantly, and while the hunters were high fiving, the animal got up and ran off like it was not hurt.Good point on the ground blind shot between lung and spine, never really think about that not being a kill shot but your 100% correct, it misses everything.
Anatomically there is nothing in there that can cause a fatal wound. What happens is that when the deer drops at the shot, the spinal cord has been shocked by the bullet passing through and causing basically a knock out.
When the animal recovers, it gets up and runs off.