One of the most common holstered weapon retention drills is to press down on the handgun, making sure the bad guy cant get the gun out of the holster. Check out the below link. The video shows a pretty good example of why using the proper equipment is so crucial. I have no idea what make of holster is in the video, but it looks like just a competition paddle holster.
Stay safe
http://www.youtube.com/watch?v=rKKx4G2dukM
