Climb the stairs and turn left. Go straight ahead to balcony. Cole of Alpha squad will be holding the Locust back.
Shoot some of the Locust to help him. Kim will order Marcus to go revive Cole when he's hurt badly. Kim will open the doors to the stairs for you. Run down the stairs and revive Cole.
After he's Revived and the Locust are dead, head back to stairs and take left set up to the top. Enter the room at the top of the stairs. Kim will open up the door in this room.
In the next corridor Kim will order Jack to rip open the door.
While Jack is opening the door Locust will attack. Kill these new type of Locust to keep them from stopping Jack. Some locust will come from the hole near Jack. Enter the door Jack just opened.
Kim will order Marcus to pick up a Hammer of Dawn but not to use it until ordered to. Go out the door to the balcony. Aim the Hammer of Dawn at the Seeder and hold the trigger. After the
Seeder is dead help kill the rest of the Locust in the area.
Follow the path around the water to the door. Kim will open the door. Enter the now open door. Go through the door on the other side of room as well.
In the hallway after the door will be a door to the left which will have a seeder down below. Use the Hammer on it. Mop up any remaining Locust after the seeder is dead.
Group up with the rest of Squad at door in room. Kim will open door. Enter the hallway through the door. Go down the stairs to the left. You will run in to two Wretches at the bottom of stairs.
At the bottom of stairs follow hallway to the left. It will lead to a hallway to the left. Follow the hallway to the courtyard with the seeder you last killed. Kim will make contact with Control. Go down the hallway on the left side of this room. Several Locust will attack in the room at the end of hallway.
Keep going forward and up the stairs on right side of room. Follow this path in to the next room. Kim will open the door to the left. Go through this now open door. Climb the stairs.