Pertwee really sold that scene with the RWR because I've witnessed people ask in what past serial did they first appear. the irony, of course, "The Five Doctors" WAS its debut. Makes one wonder how the current production might depict it.
I am puzzled why the director (or whomever) convinced the actor to leap about like a subpar ballet dancer. I think it might have been more effective if the RWR had leaned into a running position before "vanishing" and then digging in its heels upon reappearing. Someone on YouTube tweaked those shots, giving the figure a kind of "speed blur" just as it disappeared, but a better pose (other than prancing about like a pretty princess) would have helped.
Sincerely,
Bill