Final answer:
If caught in a ground flare's light on security patrol, you should immediately seek cover, find shadows or obstacles to hide, until the flare burns out or it's safe to move.
Step-by-step explanation:
If caught at night in the light of a ground flare while on a security patrol, the best action would be to immediately seek cover and attempt to avoid detection. Since the intense light of a flare can reveal positions to an adversary, one should use the opportunity to minimize visibility by finding shadows or obstacles to blend into until the flare burns out or you can safely move to a more secure location. During World War II, recognizing the importance of light and visibility, civilians were trained to 'blackout' any light that might be seen by the enemy at night. This concept still applies when it comes to managing visibility during a security patrol. If there is a teammate with you, communicate to coordinate your movements and to ensure that everyone in your group remains undetected.