Continuing from the same quote...
"... You need to learn to shoot slow in a hurry."--Wyatt Earp
"Fast is fine, but Accurate is FINAL."--also Wyatt Earp
Why I used to tell my defensive students that somewhere around 75% of successful self-defense comes through study and meditation--you have to ask yourself how much your life and the lives of yur loved ones mean to you, and as I always told them, "If you cannot look me in the eye without hesitation and tell me that you will value the lives of yourself, your significant other or your children more than the life of an aggressor who intends to take them from you, both you and society are better off that you not carry--because those who do not have the resolve to use a weapon they carry usually end up giving it up to someone who DOES, whether handing over or taken from their corpse."
You can be the best instructor for skills in the world, you can be the best builder for hardware in the world, but there is NOTHING you can do to fix someone who fundamentally lacks SHEER WILL.