Wow! Can I hang around with you?
Seriously, good job on acting on your instincts instead of ignoring them and possibly looking silly leaving the line for no good reason.
Why some people get those instincts is currently unexplainable (theories are guardian angel, ESP, sensing something and processing the info in a part of the brain which is subconscious, etc.) but hearing of those kinds of experiences is a powerful testimony not to ignore your feelings.
Also it's interesting to note that apparently you have to act on your instincts immediately or almost immediately as soon as they come on or you lose your advantage...
Another term for this is situational awareness. If the situation you are in looks bad, most likely it is. Always have an escape route/plan. The purpose of a CCW is for self defense or if you are in fear of your life. That keeps you out of legal trouble. Best plan is to avoid area that will put yourself in an ugly situation in the first place.