Rory Miller, in his books, talks about how so many martial arts practitioners love to rely on 'assumptions' _
Assumptions that _Any technique we may have 'perfected' _ in speed, power, limb conditioned delivery to elusive assailants' targets in the chaos of the fight, will stop the fight, even before it starts.
We cannot rely on a 'guarantee' of stopping anyone, especially when you begin to realize that the assailant_ fueled by intent_ and bigger and stronger_ is under a high adrenalized state that makes him almost impervious to stopping pain with a few exceptions.
The human body is capable of taking severe damage and carrying on regardless. That there are many cases around the world of people who have been punched, hit with blunt weapons_shot and stabbed in the most severe ways (bullets to head and chest, multiple stab wounds) and who still managed to keep on killing.
To this, add the fact street punks with knives/guns who will confront you for whatever reason, are generally more experienced at this sort of thing than any of us, and we will all have trouble sensing what is about to come, for the most part…plus overcoming the psychological shock when we do sense a weapon in the process of being produced, if we sense it at all.
Being aware of where you are and what you are doing at any specific time, does help somewhat. In my work it was necessary to travel and interact in dangerous cities and neighborhoods, such as trying to pin down witnesses and injured people in ghettos, like in Baltimore, Philadelphia, East Orange, NJ, Boston' Roxbury areas etc.
I.E., Once when in East Orange NJ_ traveling with my company car through an ethnic neighborhood _ while chasing down an elusive witness to a fatality, my car was suddenly peppered with ice cream cones thrown at the windshield by a group of punks suddenly appearing from a street corner I was about to negotiate.
The police said the idea was to make me stop the car to clean the w/shield so they could then rob me at knife or gun point. Fortunately I had some vision left and sped the hell out of there.
Baltimore and Philadelphia were even more menacing to my excursions there.
Most people also do not realize the lingering psychological shock on people exposed to an area of a killing by knife or gun that will affect your interactions with them in ways very unpredictable that can trigger more violence.
As an example, the day after the killing of the karate black belt by the gangbanger in the Roxbury case…the entire building's tenants complex _ was overcome with terrible fear…very few tenants opened their apartment doors to me looking for information on what they may have heard or seen…
some yelled behind closed doors for me to get lost…the few that did talk were terrified in giving me bits and pieces of what they heard…
one guy, ex military, told me he heard the cries for help, tried to get to his shotgun in the closet to get out and help, but could not as his feet were frozen to the floor.
The young girl upstairs was whisked away by the State into protective custody, and I was denied an opportunity to interview her.
Be careful of where you travel, what you do and what risks are lurking…check out the stats on crime rates before you venture out anywhere and be prepared the best you can be.
Example: see this about Las Vegas…. http://www.neighborhoodscout.com/nv/las-vegas/crime/
as one example of dangerous big cities, though death can come to you from anywhere, any place.