I can't figure out how to beat the Destroyer Armor... Any help???? I've been trying for hours!!!!!!!!!!

In order to defeat the Destroyer Armor you must enter 1 of the portals to either side of the dining hall. These portals lead to rooms where your team must fight the armor, close quarters. The exit doors open once all the Trolls are defeated in the room. After exiting the room your team returns to the dining hall. Keep entering the portals until you get to the room where Loki is and keep pounding on the Destroyer Armor until he stomps his foot. Leave the room when you are ready, to start the cut scene.