Human perception is a fascinating topic, and certainly one that you could spend the time it takes to earn a Doctorate’s Degree or more studying. When it comes to self-defense and related disciplines, it is important to factor it in to your training as well as your pre-gaming of what to do “in case something happens.”
The current trend amongst many shooters is to try to perform all tasks as rapidly as possible. Some of this trend is admirable and useful, some of it is possibly unproductive, and potentially harmful for real world encounters.