What Actually Happens
In a crisis, where weapons are fired, it is your mindset, how you use the skills you were taught, that makes a huge difference in the outcome; even more than firearms skills. Most of those skills are going to collapse on you from fear and adrenaline anyway. Only the core of "aim and shoot" will remain if you are lucky.
All of the high end techinques you are discussing regarding detailed pistol skills, will most likely fall apart in a desperate shootout. All you can hope for is to focus on an adversary and use your training to automatically aim and fire with some reasonable accuracy. Perhaps a few highly skilled people, such as trained officers, could pull together multiple skills in those moments; but even that is doubtful to me. Personally, I always try to spot cover in any situation; and I would go for it first, before I thought about standing up in the proper posture to shoot. Once I have cover, then I will go into action.
If you are taken by surprise, you will have little or no way to use firearms training effectively. Everything will fall apart and you will be very lucky to bring your weapon into play at all.
In the story mentioned above, the people who were victims, seem to have paid no attention to their surroundings. That is easy in our culture, because it is not every day that we are set upon in such a manner. But I believe that out in public, especially at night, we should always be acutely aware of our surroundings, and any anomalies in familiar fields.
There is a discipline called "field anomaly" that teaches one to note the most minute changes in fields of view. One of its tenets is that one must always be watching; memorizing familiar fields, and looking at them for any changes. Also important is watching and noting anything unnatural in a landscape. Keeping one's alertness at level yellow is sufficient to spot field anomalies. I practice field anomaly, and practice looking for cover in the places I go, much more than I am able to practice the fine points of shooting. And that is how I prefer it. I'm a good shot, but that is only part of the art of survival in a firefight.
I think that the "fear "factor" will outweigh everything but the most core training techniques when danger is in one's face. One must know how to ignore the "fear "factor" in order to fight effectively in a crisis. One must be willing to take hits and keep firing without letting emotional shock cause collapse.