You can pretty much do this with any of the civil war quests between the Empire and the Stormcloaks that have battles. Simply just kill your own side. In this particular quest, Ralof would turn hostile as I start killing, but he'd then become unhostile as I progressed on with the quest. You can acquire all Vampire Lord perks easily within 30 minutes
![](https://i.ytimg.com/vi/F37VE-kixyg/mqdefault.jpg)