This episode has many reasons that make it worthwhile repeat viewing but Claras journey from companion to traitor is the most compelling. Watching Jenna Coleman seed her performance with all the little tics and nuance that signal her upcoming reveal is riveting upon a second viewing. Give a shout out to director Daniel Nettheim who makes sure the clues are all there and yet continually misleads the audience by inserting action sequences or cutting away seconds before the realization can hit. Colemans facial expressions are a wonder as Claras mask of concern slides into cool calculation. Who is Bonnie? There are some indications she may be more than a disgruntled Zygon rebel. The cliffhanger for this episode is one of the best weve seen with Bonnie taunting the Doctor the entire time she assembles the missile launcher, takes aim and fires. Evil Clara may work especially well as this is a character who has shown us moments of darkness in the past. No matter what you think about Clara as a companion she is a complicated one and that sets her up beautifully to be the Doctors antagonist.