The problem with people learning self defense is they're too reactive instead of pro-active. They have this mindset where they'll wait until an attack happens then respond to it. In a real attack, you might not get a chance to react the way you want. It might happen so fast, you might be the first to get killed. When i worked at Wal-Mart, they made me go through active shooter training. It was a well planned procedure on how to deal with mass shooters. Shooters plan their attacks so you need to plan your defense. If you don't - you will make fatal mistakes like fail to see the threat, freeze when under fire, not take cover, etc. That's why cops and people in the military spend almost of their time training. When they get attacked, they already know what to do.