Most of us have experienced tunnel vision at some point in our lives, concentrating on one object so hard that everything else just sort of fades away. In most circumstances it’s only a minor annoyance or even a funny occurrence. But in a self-defense situation, it can be a major problem.
First, there may be multiple attackers, and while you’re locked in on the guy standing in front of you, and attacker in back can take you out. You have to stay aware of who and what is around you, even when confronting an attacker. For this you must listen to all of your senses, including your ears and nose. Feet pounding the pavement and changes in scents can indicate another attacker that you may have to deal with, or it could be someone trying to get away from the danger. You must be able to discern the difference and be prepared for whatever comes along. Also, tunnel vision can cause you to overlook innocent bystanders that could be harmed by you or the attackers.
Staying aware provides you with options, such as moving to cover or to an area that prevents innocents from being hurt in crossfire. The best decision might be to fight, but it might also be to not fight. Losing yourself to everything other than the danger standing in front eliminates your options and your greatest self-defense tool—your mind.