This is a very interesting topic from Tactical Rifleman that shooters should watch, and it is about the use of barricades in Close Quarters Combat... "You best believe that cover from incoming gun fire will be your best friend in that moment. Having a solid obstacle between you and a would be killer is a blessing in itself, but knowing how to properly use that cover is just as important.

Think about this. If someone is trying to kill you with a gun and you happen to find yourself a nice piece of wall to hunker behind, how long can you just lay low back there? If you can’t effectively bring the fight back to the killer by having a good shooting position, what is keeping them from maneuvering closer to you so that they can effectively end your life?"

Read more here.