One of important protecting skill is securing the minimum safe distance from potential hazard to protect protectee in the emergency situation, that is basic thing for the detailed security in relation to the walking formation and the distance between protectee and crowed.
This thesis is to provide the idea on the scientific countermeasure in the gun attack situation, by presenting logic on the reaction time and it\'s moving distance, on the safe distance between protectee and crowed.
Handball goal keeper\'s reaction time of 0.33seconds is applied, because handball goal keeper\'s reaction style is very similar to security agent\'s reaction style. And 4m/sec of record is applied, that is average speed of \'go and return type run of 40m\' to calculate it\'s moving distance.
Several researches show that reaction time could be improved by continuing training, similarly security agents could improve their reaction time, providing better reaction skill. The important thing is that it make big difference in the protecting result, although the shortening of reaction time is too slight.
Securing safe distance between protectee and crowed and the distance between protectee and security agent could provide effective reaction environment with \'natural protective wall effect\' by security agent