And potentially get done for brandishing a firearm, if you have to draw and point it then you should shoot it - If you have to think about it you probably should not shoot. As said, each situation is different.The point being that there is usually threatening and posturing before most closure to violence , that is the time to draw your handgun and make ready(by make ready I mean point it at your assailants centre mass) , if it's a surprise stab in the ribs without pre indicators there is little you can do training or not , and the carry condition of your handgun is irrelevant !
There is always a point of no return (no pun intended) but it is NOT the movies and one knife wound will not necessarily drop you down or kill you.
Also there's a lot to be said for keeping your distance, why is it so hard to back away - more time, more distance and more defence in court should you actually slot some scrote who deserves what he gets (Castle Doctrine not withstanding of course)!
Blu's illustration is really good. A lot depends on HOW you carry concealed and down the cheeks of your bum isn't recommended.
Time difference between drawing from hip holster concealed under jacket -v- unconcealed from hip holster: 1/10th - 1/5th of a second - electronically timed.
Time taken to step back draw from holster and place 1 shot each on two targets centre mass - ONE second! Same or less for two shots on one target centre mass. Blu, why not try it and see I reckon you can do that.