Short Barrel Shepherd has a take on the startle/flinch/response thing that merits some further discussion.
I have never been startled in real life physical confrontations or in force on force training scenarios. This is not because I am super tough or really switched on.
It’s because the encounters I’ve experienced have had a ramp-up period from observation to action. Sometimes the period is long, sometimes short, but I’ve never been startled in a fight.
And that’s been my experience as well. I’m not a professional badass, so my experience is limited at this sort of thing, but every time something did happen, there was something that set me off ahead of time that allowed me to ramp up from “Huh, that’s not right” to “Oh boy, bad things are headed my way, and fast!”. The amount of violence may have surprised me a couple of times, but there was something in the situation told me that I’d have to think fast, run fast or hit fast in order to deal with what was headed my way.
That photo over there on the right has been used in some classes to show that a flinch/startle response is natural for we primates, and therefore, we need to train that exact move into how we draw our gun.
Except what you don’t see in that picture is all the other people in the ballpark who know something is wrong, but are not throwing up their hands around their heads because, sonuvagun, they’re smart enough to realize that sort of thing is not the proper response because there is not a bat headed their way.
Yes, they were startled. No, they didn’t flinch.
How long we would have lasted on the African veldt if all the monkeys in the tribe reacted the exact same way to one of their number getting eaten by a leopard? We would have never made it out of Olduvai Gorge, and the world would have been ruled by sentient house cats, or something.
We vary our response by the nature and proximity of threats around us. Always have, always will, and your training better darn well reflect that.