I don't know how unrealistic it is.
Josephine's reasoning is exactly the reasoning Muslim suicide bombers offer for their willingness to inflict "collateral damage" by setting off explosions that kill both infidels and Muslims. Also, medieval justifications for torturing heretics (so they'll recant and therefore avoid the greater harm of going to Hell).
I wrote the following on my blog last night. I thought that I'd run it past an intelligent audience. Note that what I have referred to as an idea is what we here at lesswrong would call a 'belief'. I changed the name to remove any strange foggy baggage that might appear in the heads of potential readers who are not familier with belief vs belief-in-belief and other concepts like that.
What are your thoughts?