Maybe he just watched it over and over and over again. Like some form of sick sick self punishment? It's not like he can watch his own parents' murders (except in his head). He sits in the dark and watches the tape to remind himself that failure is not an option, this is what happens to nice parents with sickeningly adorable kids when he's not always alert. In this scenario, he might also be listening to emo rock and styling his hair after putting on some eyeliner...