When confronting Balak at the main facility on Asteroid X57, Shepard has the choice to either allow the research team to die from an exploding bomb, or to let Balak and his bodyguards go to save the researchers. If Shepard allows the research team to die, a battle with Balak and his bodyguards will take place.
Bodyguards carry standard weapons and have light shields. The Bodyguards will tend to move around to flank their enemies and typically seem to move as a squad. Because of their assault rifles they are good at any distance at taking out their enemies.