Light-bridge Elites

When you need to take care of the Elites that guard the switch to the light-bridge, one idea is to go over to the open area left of the passage ramp and lob plasma grenades so they land in the passage at the back. You can often kill at least one Elite this way; see if you can get them all. You could lob a pattern of three, trying to sandwich the unseen Elites in between so they're caught by at least one blast. Another sneaky tactic is to jump up onto the sloping surface from the bonnet of a Warthog, creep up and ambush the Elites from behind.