Instructions
Kill the leaders of a pack of alien thugs you encounter. The apelike Brutes command the Grunts in "Halo 3," and although the Grunts are treated poorly, they also have a feeling of relative safety when their towering leaders are alive and well. Slaughtering all nearby Brutes will send the Grunts into a fearful frenzy and may incite a plasma grenade-fueled suicidal attack or two.
Take cover, while leaving as many Grunts alive as possible. If there is no longer a Brute around to command and protect them, the Grunts will become sloppy and disorganized. By allowing the Grunts a minute or two to panic alone, you give more of the little aliens time to consider a suicide run.
Pick off the Grunts one at a time to thin the pack and to make the survivors more fearful if they continue to attack normally. Suicidal Grunts don't usually appear unless there are only a handful of them left and the chances of their survival look slim. Kill a Grunt, wait for the reactions and watch your back. Suicide Grunts have a habit of flanking their enemies.