One of the Guru´s of tactical shooting, late Col. Jeff Cooper has said: "Rule number one in a gunfight - have a gun".
Unfortunately merely having a gun is not enough to survive life-death encounters. You also need skills to operate your firearm efficiently, know its limitations and abilities, be able to assess the situation, etc. All mentioned combined turns into a sort of "martial art" which includes use of edged weapons and firearms as well as physical hand-to-hand combat skills, and those mixed develops a base of knowledge and skills you need to survive situations we, again, hope you never encounter. Unfortunately there are many people among us who have had to face such situations (and are here to tell us about it), and there is no guarantee that we will not have to face our "dark day" sometimes in the future.