 Briggs ' portrayal was well @-@ received by the production team : Graeme Harper " loved Caan 's giggling " and requested " more ... on every take " ; and Davies described Caan as " the creepiest Dalek yet " . The finale also introduced minor changes to the Daleks : the characteristic Dalek " plunger " was replaced with a gear mechanism for scenes that featured Davros ' guard : the mechanism is used to control Dalek machinery aboard the Dalek flagship Crucible more efficiently ; and the Dalek eyestalk exhibits a minuscule twitch in scenes , a characteristic added by Graeme Harper to make them appear cautious and " on @-@ edge " . 
