Which wall are you at? Ignore the busted door, and keep going until you hit a dead end (if you could get through that door and turn right, it would be the wall straight ahead that you need to get to the other side of). There is a row of brick/stone across the wall about 3 or 4 feet high (looks decorative), with a pressure plate near the middle; just stand near and move your crosshairs along it.
If there was a skill book there, I need to go back...
