A man with a gun decides to rob a crowd of people. As soon as one the primary victim finds an opening, he draws his own weapon and defends himself.
A man with a concealed weapon plays the victim just long enough to distract his attacker. As soon as the attacker is distracted, looking at his loot from the minor heist, the man draws his weapon and stops the threat. It was his tactical patience that enabled him to defeat the on-going threat. Had he acted earlier, he may have been engaged in a direct fight for not only his life, but the life of others around him. He made the best possible decision in the instant he saw an opening.
Your security is your responsibility. Law Enforcement Officers will not always be present when bad things happen. When they do happen, you need to be prepared to fight for your own safety, and the safety of those around you until the professionals are able to arrive on scene.