I would quite like to see the series end on a bit of a cliff hanger. perhaps some sort of suggestion that ian and dawn find thier father, its hinted at and we are left with a voice of the father, but we never get to see him. might be the back of the head, or sat behind a chair.
Or something quite touching… perhaps ian and dawn are forced to go thier seperate ways… and they simply have to say goodbye to each other and realize how dependent on each other they have become.
or maybe something very dramatic happens, the doctor Dawn got the list from originally has reported her to the police, and they are tracking her down. perhaps they get her and it turns out that she took the wrong list? …. just thoughts
I think Ian should get shot properly. Not to death, but nearly. And they shoudln't find the dad until they've found all the siblings.