How valid are Gun Disarming Techniques???

If you are untrained, yet find yourself in a do or die moment, 2 things to remember. And it's not where your a$$ is to kiss it farewell. 1) U need to move in the opposite direction you intend to move the end a projectile will exit. 2) U want the body of the weapon (if possible) to exit the grip of the holder. So move barrel out & away from the palm of the holder. 3) bonus warning. Expect to get shot, but act anyway.