Why would you want to get past that door? It leads to the same place you can get from somewhere else..
if you are not fibbing how do you get to that place behind the door then?
I've explored - I'm positive - all of the Northlands. And I can't get passed that door, not even on the other side. But I have managed to kill everything North of the Wall - which was meaningless because the Charr still somehow managed to come back to life and use the altar I cleared to Sear everything.