How did this hit kill a deer?

Sorry no pics.

Took a quick shot that I immediately regretted taking. Went to take a look for blood and he was dead where I shot him (in tall grass right beside a pine thicket)

I hit him high and clipped the very last rib on the left side exiting behind the ribs on the right. I did not hit heart or lungs (obviously), somehow missed the stomach and was not high enough to hit the spine. As I said, he dropped where I shot, very little blood on the ground and what was there was very dark. Not sure how quickly he died but I saw no movement after the shot and he was dead when I got there (265 steps).

I assume I hit the liver but did not notice terrible damage to it. Maybe I hit the diaphragm and the main artery but I don't see how that would drop him immediately. Also, did not notice terrible bleeding when we cut him open.

Basically, looking at the shot I would have expected to trail him all night and probably lose him to the vultures.