Imagine getting trapped in a firefight against an enemy whose goal is to kill you and your team. If you're unable to stay calm, think and be confident in yourself. You can be the fittest person in the room, but if you freeze with fear, you're useless.
The ability to stay calm and confident during life-threatening situations is what you want. If our minds can't stay calm, we can't focus, and we lose belief in ourselves. Through training your body, your mind will be embedded with the tools to stop thoughts that cloud your courage to take action.