Fellers, there is one more verse to this discussion. Even if you have your firearm in hand, unless you are ready and willing to pull the trigger the INSTANT that predator who is 30 feet away moves toward you, he will likely still get you. If he has a knife, he may die from the round you may get off, but he will die after he sticks you with the knife!!. Reaction time is an interesting thing, but I can assure you, IF you hesitate, you are lost!! Don't even think you have a "shot" if your weapon is holstered or in your pocket. If danger is that emminent, it needs to be in your hand.
It is a hard thing to say or think, but you must be certain and settled in your mind that you will use your firearm. If you allow the preadator to make you talk, and if he starts moving while you are actually talking, you are beat, even with your firearm out and pointed at him. Again, you may get a round off, but he will be at you by that time, or very nearly so! If you are talking, it will take about 3/4ths of a second (at best) for your brain to change gears from talking to acting. If he can move 30 feet in 1.5 seconds, he is now at 15 feet. If it takes another quarter or half second for the hammer to fall, where is he now?? And what if it took you an additional half second to change gears??
This is an interesting proposition, but if you want to prove it, get a rubber knife and a rubber gun and try it, over and over. It works,even if you know what is happening. Just remember that any time you are giving instructions to the predator or housebreaker who is threatening you, your trigger finger is idling in neutral while your gums are clattering! Keep your commands short and sweet. Let your firearm do as much talking as it will, both before firing and after. Let the sucker wonder what you are gonna do.
If you are truly made up in your mind, and if you are confident that you are justified and righteous in your use of deadly force, and if your equipment is in hand and functional, all you really need to do is look the predator in the eye and smile!!