I applaud the work of the OP.
I am not a mathematician, but a cop.
I have seen people dead of one shot, I have seen an officer that was shot up so bad he was bleeding IV fluid and lived. I have seen people fire one shot and its over, there was the famous FBI Miami shootout, where one Agent fired 15 shots laying across the hood and missed them all from 3 feet. Statistics are worse than anecdote.
There are too many variables, how many BG's have soaked up 8-10 shots from 9mm, 45, 357 mag and still kept fighting? It is a sobering read and interesting in that, the case you are presenting is capacity trumps all. There are a lot of assumptions in your argument. Stress is just one thing to add to the pot, you may be diving for cover, shielding your daughter or what have you.
How do you train? How do you practice? Proper training and practice will sway the odds in your favor. I am a big advocate for point shooting - not hip shooting. Bring the weapon to eye level, look where you are shooting, muscle memory and peripheral vision will bring the shots in. Point your finger, look where you are pointing, it is that easy out to 15 yards.