"And draining life force is somehow less crazy and also an infinite power source?" If it wasn't going to last it was because the energy wasn't self-sustaining, not because it came from one source or another. It was interesting though that she thought such a thing was 'too easy'. Easy for who? For that matter, why was it that only outsiders could render this invaluable service, and how exactly did they get by before they started kidnapping people?