I'm doing the quest "Siege on the Dragon Cult" and I am stuck in the refractory. When I first went through the dungeon, I came to an iron grate that would not open. A draugr then came out of a room behind the grate and after a minute of looking angrily at each other, the grate came down. After I dispatched my undead friend, I proceeded with the rest of the dungeon until arriving at a puzzle door. I didn't find a claw at first so I searched the dungeon and finally found the glass claw. However, the grate is back up and I don't see an activator on my side. Did i just biff the quest or is there a way forward?

(P.S. I'm playing on an xbox 360)

reload an autosave from the dungeon if you cannot find a way through.