Brock is right: the fact that you've twice botched trying to teach yourself what amounts to iajutsu or fast draw in weaponless combat doesn't mean that you haven't got the skill described adequately; it means that to this point you've not been able to make the transition from a notion of how this might be done to actually doing it successfully.
I suppose I can illustrate it thus. When I was knee high to a grasshopper, I and my brother and his girlfriend next door taught ourselves how to walk along the tops of split rail fences--what in Multiverser terms is balance beam walking but under adverse conditions (a balance beam is wider and sturdier and flatter than the tops of such fences). From that experience I can explain how I would walk on a tightrope. I can conceptualize it quite clearly in my mind, and even translate some of the tricks (standing on one foot, walking backwards, turning around, walking with eyes closed) I did at five or six years old on a fence to similar concepts on a tightrope. However, I have never attempted it--and the fact that I can conceptualize how to do it and have a related ability (I still walk on fences and curbs and other narrow ridges from time to time) does not guarantee that I won't fall and break my neck on the first attempt.
In the same way, the fact that you can describe exactly what you want your body to do does not mean that you can get your body to do that the first time, or the second time, or the Nth time; nor does it mean that you won't hurt yourself trying. Being able to shift from not ready to ready in an instant is more difficult than it sounds, and even those who are very good at it do not always succeed.
It is also not that simple to "try" it in controlled conditions. After all, you're in your room, you put your hands up, you think in terms of being "not ready", and then you attempt to shift to being "ready" instantly--but that's not really the same as standing in front of the man holding the gun who has told you to raise your hands, and then at the instant when he glances at his partner you move into stance and strike. The fact that you were able to get into stance from having your hands raised when you were in your apartment does not mean that you necessarily achieved it as that kind of instant readiness application. You're attempting to train your reflexes to do something instantly that they do adequately. You can't expect immediate success.
So it comes down to trying again.
--M. J. Young