Corrected entry: Heath's priest buddy (Mark Addy) began encouraging Heath to leave the order and marry Shannon S's character right after they got to Rome. Then, Heath decides to do just that. Suddenly, Mark Addy changes his mind and says he should stay - giving an impassioned speech in the hospital about their mission, training, etc. Why the big change of heart? They were already fighting the Sin Eater at the beginning, and so far as I can see, nothing had changed.
Corrected entry: Why, oh why would a priest who was committed to exorcising demons and banishing ghosts raise two demons to live in his front hall? What was the purpose? Even after he was excommunicated, he wouldn't do something so stupid as that, surely.
Correction: Wrong.. We are not sure if the priest brought up the demons. This part of the movie is really never explained. Even Alex (Heath) isn't sure.
Correction: This is not the case at all. Mark Addy is trying to convince Heath to kill the sineater after Heath decides there is no problem with what the sineater does.