I've run through this a couple of times. The first try I was able to make it to to the caravan ambush and grabbed the lamp but after fighting the Absolute forces the Harpers turned hostile. I finished them off and continued on, but later I go back to Last Light and walk by a random Harper near the cellar and suddenly EVERYONE in Last Light goes hostile. I reload an earlier save and keep Isobel from being captured only to have the entire INN go hostile again? Is this a bug or am I just royally screwing up somewhere?