Out of the three options for body doubles that were provided to us in the season - Teselecta, Ganger, time-stream double - I think the Teselecta is really the only one that could have worked. Amy's time-stream double could only exist within the Two Streams facility, and even the Tardis couldn't support the paradox of them both existing together, so that's out. Once a Ganger is killed, it just dissolves into liquid, and certainly doesn't regenerate, which would have given the game away immediately. And the Doctor would have had to be elsewhere to run it, whereas the "fixed point" stated that the Doctor had to be on that beach at that time.Rather than the Tesel-whatcha, I would have preferred to see the Doc use a Doppleganger. Mostly, because gangers were used, not once, but twice against the Doctor, and it would have been interesting for him to fool them they way they fooled him. I think the one reason this had to be ruled out, though, is that the Doctor-ganger that was created was a living, breathing, thinking, everything, duplicate person, so killing him would be something the Doctor would oppose. So, maybe not. Well, maybe if the Doctor-ganger could be kept solely a meat-puppet, and not indepentently alive.
No, the Teselecta is the only way for the Doctor to both be present and be protected at the same time. I just have to hope he Tardis'd out of there before they set the body on fire.
My problem with it is more that, in "Hitler," the Teselecta moved stiffly and made obvious robot noises. Whereas in "Astronaut," The T-Doctor moves smoothly and naturally. That's necessary to pull the wool over our eyes, of course, but it's a definite fudge to make it work.
I'm sure that's exactly the plan. At least I hope.But, how would the answer cause the Silence to fall? Perhaps that will be the angle on the season, how the answer to "Doctor Who?" will cause the Silence to fall.
The concept as I understand it is that the Doctor knows some massive cosmic secret, something that's associated with his real name. Moffat has been playing with that at least as far back as "Fireplace." And that the Silence believe that he will reveal that secret - that he will be unable not to - at some point in his relative future. And that the reveal will have catastrophic consequences. And therefore they want to kill him now to stop that from happening.
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