So I was doing this quest, and got to this part. I go to the basemant, talk to this Davison guy, and agree to help him get rid of the other guy. The other guy asks about the status of his friend, so I go down and check, come back up and give him the news, he leaves, and I get the intel Davison wanted. I go back to give it to him, and he attacks me. I kill him, and now I'm stuck at this stage of the quest. I killed all the Nightkin in the basemant I could find, looking everywhere, but none to be found. How do I fix this?