Nobody should ever stand out in the open and trade bullets with a bad guy!
As soon as bullets start heading your way you need to find some cover and quick!
Buy what is the difference between cover and concealment!? and How do they play a role in surviving a self defense senario?
First we can stat off by defining the two terms.
Cover "is protection form the fire of hostile weapons"
Concealment " Is the protection from observation"
So what does that mean? Well what it basically means is that anything that is capable of stopping a bullet from hitting you is cover, where as anything that is capable of hiding you is concealment.
For example a wall in a home is concealment, because no one can see you behind it, but it is not cover, because bullets can easily travel through the wall. Somethings are both cover and concealment, for example a cement wall. An example of something that could be cover but not concealment would be bullet proof glass. You can easily be seen behind the glass, but the bullets can not make it through.
So what makes good cover? Materials that can stop a bullet such as steel, concrete, water, packed earth, or thick wood.
What makes good concealment? Ideally good concealment will allow you to observe your surrounding and the "bad guy" without them easily being able to see you back. Things like leaves, netting, shadows, and fabrics can be great items for concealment.
Your first priority in any active shooter scenario should be to find good cover! From there you can think for a moment, access your situation and make a plan. if your decision is to try to eliminate the threat, or to try and escape the threat, then you should move from cover to cover or cover to concealment if no other cover is available until you are close enough to eliminate the threat or far enough away to escape the threat.
Some basic rules for cover are to remove or mute anything reflective or noisy on your person that can give away your position such as a cellphone, sunglasses, watches, earrings, and reflective jackets or bags.
You also want to avoid contrasting. That would be like if you are wearing white and stand or run in front of a black wall that will catch someones eye because of the stark difference between the colors. You also want to avoid standing or moving in front of a light source. This can easily alert everyone around to your presence.
If you have any questions please don't hesitate to reach out.
Stay Safe and Stay Ready.