When faced with the Actual possibility of death, people will do extreme things. Especially if their children are threatened. I doubt many of us in fhb have ever been in that situation.
While a poor parallel to draw, consider any blockbuster tv show concerning survival. Lost, walking dead etc. We enjoy these shows as they sometimes probe the dark side of our humanity. A common theme in all these shows is how easily man will kill his fellow man in order to better the survival of himself or his kin.
Humanity is Lord of the flies at it's core.