Use the corridor outside the rune door room to kill the wizards, as soon as they rush, retreat to top of hallway and snipe with Icebreaker. When you get to the large circular area, after the room with the Ogre and Knight, instead of turning left and heading towards the two big yellow health knights, turn right, you can approach the 2 knights from behind and sneak past.There is ghost on this route also. When you go left use the door frame to jump into the blocked off area. Its also a good place to Icebreak any hive getting off the two drop ships.