So, I was doing the story missions and Variks gave me the bounty/mission for the Shadow Thief. "Okay," I thought. Started it up; no problems. Killed the Fallen walker; everything's okay. This is where things started messing up. The door where Taniks (is that right?) appears kept teleporting us to the start of the room. If this ever happens to you, just wipe. It will solve itself.