This is really a very different episode which covers something happening around us. Do we have family member who was mentally unsound or suffering from depression? All this girl wanted was to be normal and loved by a man she likes.
She saw her boss, a man whom were so nice to her though he knew she was ill, she was willing to kill his girlfriend after knowing their relationship and blaming it on something evil in her that needs priest to help remove it.
This is something very tough for her mum and brother as they have tried their best to help her. Felt sad for her for the outcome. (Feeling what Martin was feeling I guess)