In my experiance the Army training methodology is the quickest most efficient way to convert fear biters into cold blooded killers...
...and the ability to remain self-possessed and NOT over-reacting or resorting to "spraying and praying" when under that kind of pressure.
That is one of the greatest benefits of this training methodology (which is very similar to the current police force on force training paradigm, at least with agencies that are cutting edge).
You create people who are more confident with use of force, which in turn often makes them less apt to use force inappropriately. Force Science Research Center showed this with some studies on Simunition f/x scenario training. The more exposure one has to such things the colder one's blood gets, so to speak. It sounds harsh, but it actually saves lives.
FWIW, if you are training appropriately, under realistic duress with realistic dynamics, I have learned that is about 2/3ds the battle when the bullets (or the blades, or what have you) are real.
The other is more personal: and where I think the true warrior mindset comes in. Training in progressively more demanding force on force trains the mind and body in much the same way combat sport does: it makes you physically tougher, and it refines your tactics and technical proficiency.
That other 3d is in being "okay" with facing death. I disagree with some classic bushi writers on the warriors job being "to die." Facing death, certainly, but anyone can throw their life away. I think Musashi pointed that out.
One must be absolutely willing to face death;
but absolutely unwilling to die.
I have only two reasons for doing so (putting myself in harm's way): to protect my family, and in certain rare circumstances in my professional duty. I have only had to face the latter situation. Thankfully!
To bring this home for the majority of readers, something to chew on and think about and "get right with" when they consider how this topic may relate to their own training in aikido and self defense:
Visualize frequently. The way that I think it was Suzuki Shosan said a warrior must daily meditate on his death in various and sundry ways to get accustomed to that thought.
He's partly right.
I change one thing: daily meditate on facing
death, on all sorts of hideous scenarios on threats to your person and to that of your family.
But ALWAYS stay in the fight. Literally visualize being shot in the face and continuing the fight to save your family and yourself. Don't always be the "easy" winner, but come up with almost impossible odds and defeat them.
Come up with different responses to the same scenario, but always
The way I like to put it:
Be a Warrior, not a Worrier.