There are a number of sound self-defense principles mentioned in this video. We can learn a great deal from professionals who deal with violence on a regular basis. The real world provides valuable lessons.
Police and security personnel are dealing with situations similar to we civilians in that it is not always clear someone is attacking or initiating aggression until they have already made the choice and have begun their attack. In a sport fight, it is clearly understood that a fight is about to occur and when exactly it starts. From that point on, every movement is treated as a potential attack. Each fighter moves to respond to the movement of his opponent. You usually see a LOT of shifts, steps, weaves, and other adjustments to keep the desired range and angle to the opponent.
Real life environments are totally different from martial sports. Violence is usually unexpected (at least to the target/victim), with very little or no lead up to an ambush or assault.
How does this relate to us, as peaceful civilians who wish to keep ourselves protected and prepare ourselves should we have to face violence? How does this affect our martial arts training? We must make sure the principles of self-protection and self-defense are at the heart of our training. As I stated above, this video brings up a number of them.
1) Action beats reaction
2) One thing at a time
3) Understanding range is critical
4) Forward movement is superior to backward movement
5) Get off the line of attack
A main similarity we civilians have to police and security professionals is we can find ourselves suddenly in a situation which we have no idea of what is happening. We need to observe, evaluate, and decide whether a physical intervention is required. Of course, if we are attacked, that decision is easy. As stated in the video though, if the attacker makes the decision to be violent he is at the advantage. His action is ahead of our reaction, as we are likely still evaluating.
As martial artists, we can expand our training to include approaches from all directions and attacks begun at all ranges - especially close (conversational) range. Someone standing within arm's reach of you is mostly likely where physical violence will start. Yet, in the dojo we almost always start well outside this range. Another principle: You get good at what you practice, and are not good at what you don't practice. It is best to make sure your training incorporates this principle. You can be creative with how you do it, but if you want solid self-defense skills, your training must include these variations. Doing so, you will find out what works and what is problematic and get a firm understanding of range, positioning, timing, and speed.