Thats where i have shot the 5 deer i have lost in my life. Also where a friend shot a nice buck and discribed the hit and blood trail to me that sounded the same as the few I lost. 2 weeks later it was back on camara like that one with healing hole from the arrow in its back.
I agree with you 100% on this spot being a survivable hit. I do have a theory unproven that it also depends on if the deer is inhaling or exhaling and where at in the process. That if its fully exhaling at the hit lu gs are deflated opening a space. But if lungs are expanded that space gets smaller or eliminated.
i like that theory
I also think think what part of the pump cycle the heart is in when the bullet hits has something to do with how the deer responds.. would explain why some deer drop and other run some with the same exact shot placement.
Explanation. When the heart is at full contraction blood pressure thought the body is at max. Whe a bullet hits than it short circuits the system driving the pressure higher from impact and hydrostatic shock. But if its at the relaxed stage the system can handle the increased shock and pressure better.
But these are just personal theories that make since to this dumb hillbilly with no scince I know of to back it up.
Edit. Once when I was 17 I had a large chunk of lung blow out of a doe I shot with 12 g rifles slug at 5 yards on the entrance side sending it over my head. That the only time I have seen that and trying to figure out why is what got me thinking about pressure, expansion, and what stage body parts and systems are in at impact.
A spike through the blood system when its already at max pressure increases pressure in the entire body including the brain. Easy to see how that could increase droping in their track at least to me.