ORIGINAL: Schultzy
The lungs are your biggest vitals, keep that in mind! Don't be so concerned about going for that heart shot on a quartering away animal, stay away from that shoulder and go for them lungs!
I don't think you are imagining the distance and angle of situation 3. On an animal that's severely quartered away you cannot get both lungs. (though I don't know from experience).
Considering that a single lung shot is the last thing you want on a deer, why would you still want your arrow to come out as you stated? As big as the lungs are like you said, when I think about that situation, the arrow still only gets the far lung.
Tell me what I'm not thinking about here.