[Now that I've done all this, someone point out how long ago someone else did it much better. :)]
In reading a recent blog post by Rory Miller, he was making the point that there are visual cues related to detecting a physical attack specific to short range encounters:
There are ranges and positions where someone can stand and hit you without any telegraph. The threat has to be in range (drop-step exception) and have their limbs in certain positions. This is a code red thing, or what Marc calls "1". The bad guy can hit you in one motion.
For the most part that's not true. Even in range, most positions require you to shift your center of gravity (CoG) before delivering power (again, there is an exception for the drop step. I love the drop step). Marc calls this a "two". It will take two motions, a precursor and the attack itself, to do you any harm.
"Three" means the threat has to change his foot position (and the drop step, in certain positions turns all three to a one... very cool) as well as shift CoG.
I spent a lot of time in close proximity to very bad people. More than a few commented on how relaxed I was. It's powerful. Relaxation can be disconcerting, it makes the criminal think that you know something he doesn't. This was why I could do that. Not only could I tell if the bad guy could reach me, I knew, in advance, exactly what he would have to do or where he would have to shift his center in order to attack. I knew when I was safe and I knew exactly what to watch for should the threat try to move.
This is close range, from a maximum of 3 yards/10 feet to handshake distance. Any attack initiated within these distances simply cannot be reliably defeated by resorting to a holstered gun, whatever it's condition or method of carry. For the determinedly argumentative amongst my gunnie bretheren and sisteren, I will happily stipulate that an exception is indeed possible to almost any given general postulate such as the one offered herein. I simply am not agreeable to staking my life or anyone else's on the likelihood of such appearing just when needed most, thankyouveddymuch.
At the other end of the scale is long range - for the design of pistol/revolver one is likely to attempt to carry (commonly concealed) on their person. This is when "strategic thinking" comes to the fore; how attractive a target are you relative to others, is this an actively disputed part of town by rival gangs, any recent "social actions" (read: riots or demonstrations) in the area? Things of that general nature, factors not directly related to you necessarily, but relevant to the decision-making process. Go/no go, alone or in a group only? You can't completely predict specific occurrences, but you can develop techniques for measuring the relative likelihood of extreme events occurring in a general locale during given times or other metrics.
The local Walmart parking lot at 9:30 am on a Sunday morning? Almost certainly too early in the day for most of the criminally inclined segment of the populace as well as the - how shall I put this? - the more socially restrained segment of the Walmart clientele? The exact same terrain at Midnight Friday night watching the drunk college chicks stop in to make a quick purchase? Much more entertaining (ask me how I know :)), but also more likely to attract others willing to seize the opportunistic moment as well. Same business locale, same basic social function taking place, entirely different levels of threat involved. Long range SA, assessing and identifying the conditions that contribute to a threat of violence being more or less likely at a given place/time of day, and that can be accounted for and efforts taken to negate.
For the purposes of this proposal, I'm going to stipulate that these are threats of attack that can be identified from a minimum physical distance of 15 yards/50 feet away, regardless of the time of day or locale. That's a distance of 5 to 6 cars parked side-by-side or three or more aisles away in a store setting. Plenty of distance to physically escape or create a defensive or hide position (with greatest emphasis on the first of these - RUN).
A carload of rowdy individuals get out of their car(s) in the same parking lot aisle you are walking down towards your car. You immediately walk between parked cars to the next aisle over, keeping track of them while not making direct eye contact. If they follow into your new aisle, change to the next, now openly watching them. Consider beginning a trot/side-step/backpedal towards the store entrance instead of your car. If they continue an aggressive advance, dump the groceries and sprint for the store entrance (or car if that should actually be closer at this point). Draw your firearm only if you have no other alternative and aim center mass at the nearest target until they retreat or they overwhelm you (an event not to be ignored - but your gun might be more effective as a hammer at that point). Never threaten, never try to intimidate; if someone intends to attack you it won't stop them and might attract the attention of the one who hadn't quite decided yet.
End of story. Maybe.
A common enough situation that might degenerate into violence and taken to it's ultimate point of potential conflict. I hope the many steps available to avoid or escape are self-evident.
So, that leaves the mid-range of situational awareness, something that makes itself apparent between 3 and 15 yards away. These are the toughest to defend; the least amount of time/distance within which to make an assessment and decision before the attacker's action makes the choice for you. Even someone like myself, who determinedly carries a 1911 in Condition 3 (Yo, Weird, pffffft! :)), has time to draw, cycle the slide to load a round in the chamber, aim and deliberately fire OR make an effort at escape, but not to think about it much. Mid-range threats aren't those that transition from further out (like that illustrated above), but only appear after you are too close to easily decide on a response and take the action. If the threat is directed at another you might have some additional time to make a judgement in, but you can't count on it. This is gun range, but that isn't a cut and dried option to choose.
I've got no advice to offer on this particular circumstance except to note that, absent some legislative mechanism specifically exempting you from it's application, it is a tenant of American law that no one can pre-emptively defend themselves (or some other person or property). There has to be an after-the-fact demonstrable direct threat of physical violence or death being imminently offered to justify a ruling of "not guilty" (or a Grand Jury "No Bill") if you kill someone. Most especially if you offer the spontaneous confession of homicide that is the plea of "self defense", which are the last words you ever want to come out of your mouth should you become involved in a shooting.
If you say self defense at any point during the investigation, you just freely confessed and the po-po are released from any further consideration of Miranda (or pretty much any other rights you had up to then) as regards the admissibility of any questions asked of you, any answers you might make or evidence gathered from you thereafter. Let me be clear on this, if you make a claim of self defense you just confessed to homicide, and assert that the evidence the cops gather will support your additional claim of an absence of any criminal guilt on your part.
I will offer this advice, surrender to the law peaceably, present your identification willingly, and then decline (politely) to answer any further questions without the advice of your legal counsel. Oh, and memorise your lawyer's phone number; Officer Friendly won't be at the crime scene, or during the booking process, and your cell phone will be taken into evidence and unavailable to you once the cops arrive on-scene.
If you doubt any of this last bit, rent your own lawyer and find out for yourself.