What is the recommended action if you see a brilliant flash of light?

Dropping flat on the deck and covering your eyes is the recommended action if you see a brilliant flash of light, particularly in a military context. This response is appropriate because a sudden flash can be indicative of an explosion or a bright source of light, such as a flashbang or an explosive device. By getting low to the ground, you minimize your exposure to potential shrapnel and blast effects that could occur from an explosion, thereby increasing your chances of safety. Covering your eyes helps protect your vision from any blinding effects that may result from the intense brightness of the flash.

In contrast, running in the opposite direction could be risky if the source of the flash is close or if there's additional danger present. Looking directly at the flash can lead to temporary or even permanent vision damage, which is why protecting your eyes is critical. Shouting for help does not provide immediate protection from the potential danger posed by the flash and may divert your attention from assessing the situation properly. Thus, the recommended action of dropping flat and covering your eyes prioritizes safeguarding yourself in a potentially hazardous scenario.