Forum:Archangel

Ok, so I appear to be stuck during the mission to aquire Archangel. After the first wave of mercs, he has asked Shepard to go close off three shutters in the basement, I've closed the first one but I appear to now have no-where else to go, the door through to the garage has been locked by Archangel and the way to the utility is obstructed - am I just totally missing something obvious or is there something I should have earlier? Any help would be great!