In the level Crow's Nest, where Miranda Keyes, Sergeant Johnson and the Arbiter board the last Pelican dropship leaving the base, set a Deployable Cover outside the door that the second wave of Jump Pack Brutes emerge from. Kill the Brutes that are present, and return to the Deployable Cover. Disable the shield, but do not destroy it, to enter the room. The Brutes present will no longer regard the player as an enemy, and although they will look at the player, they will not attack. If the Deployable Cover is destroyed, they will continue to exit the chamber and will regard the player as an enemy.