In the Collector why does the guy breakin in have to protect the family?

i was asking myself the same question. Why doesn't the dude just steal the money and leave

If you went into the house and walked into the cellar looking for something to steal and you saw a brutally bleeding man, a young terrified girl and a woman crying for help, your telling me that you would leave? That's being an ungrateful bastard, if you were held hostage and somebody came, you would want somebody to help you. The premise of the movie is this guy was about to commit a crime and continue his cheap dirt bag ways, but then this opportunity comes and he finds the self-righteous in him to protect this family, it's actually a good moral.