Davies wanted the Doctor to realise that Rose has something to offer to his cause. Their holding hands while running was meant to signify that they were a team, despite him not asking her yet, and they were not to question their relationship. The episode was intended to be presented from Rose's point-of-view. For audience identification purposes, Davies wanted the alien menace to be easily mistaken as human, so that it was possible for Rose to mistake the aliens for humans. Davies felt that there was no need to create a new monster, as the Autons met these criteria. The Auton sequences were difficult to film because the costumes were uncomfortable for the actors; which meant that frequent breaks from filming were needed. Computer-generated imagery (CGI) was used in post-production to cover up the zipper on the back of the necks of the Auton costumes. Davies wanted to recreate the scene of the Autons breaking out of shop windows from their first appearance in "Spearhead from Space", although he had the budget to actually smash the glass instead of just cutting around it like in "Spearhead".