American military slogan

Fire in the Cave comes from World War II and Vietnam War. When American soldiers throw grenades into a hole, they will first fire a gun in the hole to remind people around them that there will be an explosion soon. Later, this sentence was used and became an idiom for American soldiers to remind their companions to avoid before returning grenades.

Target down, target dead

Cover my six o'clock, cover my six o'clock (the back hemisphere)

Find the enemy coming. Find the enemy.