You don't wanna know Tang Soo Do if you've got assassins on your ass. You want to have good cardio, and you want to know parkour and Krav Maga disarms. The best thing to do if caught unarmed against a handgun-wielding attacker is to run. If you're ambushed at very close range, and they're not trying to mug you but attempting to kill you straight away, you have a tiny window of time to react and attempt a disarm. If you fail, you're going to be bleeding to death out of a hole in your neck in a second or two. If they reveal themselves from a good fifteen yards away, turn and sprint in the other direction, occasionally darting and changing course to make your movements harder to predict so they can't get a good bead on you. Most handguns aren't super-accurate beyond 25 yards. The faster you can increase the distance, the better. Try and put an obstacle between you and them as quickly as possible. If there is a corner, turn it. The ability to quickly vault over low walls is also useful. At the very first opportunity, you want to whip out your phone and call 911. The more shit you can put between yourself and your attackers, including cops, the better.