I initially thought he went a little bit far by following them but he then redeemed himself by telling her she was ignorant and arrogant.
When they come to my door I always manage to befuddle the gimpy trainee fairly quickly and get into an argument with the other one, I do enjoy it and wish that they came round more often.
As for the comment above about being careful about arguing with atheists 'who know what they are talking about', the 'what' you refer to is simply whichever bunch of twaddle the person at the door believes and and, pretty much invariably, atheists who have actually taken the time to research the beliefs of others are given no respect for the fact that they have done this and therefore made a more informed decision about their own beliefs, they just get preached at by the ignorant and arrogant drones at the door.