Well if don't have that specific scroll, you don't have to worry about the barrel issue. What were you doing that you'd break the barrel in the first place though??
From what I've heard, the Doctor sends you an invitation after a certain quest is completed (sewer related). And he does have something to discuss with you if you don't have Lohse. So I think it's possible for you to enter his house.
Last edited by Try2Handing; 15/10/17 10:27 AM.