Theory:Doctor Who television discontinuity and plot holes/Nightmare in Silver

• When the Doctor refers to using up his current regeneration and not knowing what his next life would be like, is this a reference to the Valeyard, and thus the 6th Doctor reference for this episode?
• When the Doctor bluffed that he is about to win the game in three or five moves, that would not require the Cybermen to invest a significant effort to verify. A 6-ply (three move pairs) look-forward in chess game does not involve that many different combinations even if they are checked using brute force. In fact, a typical desktop computer of today can do it in a few minutes, and I'd presume the Cyberman is more efficient than a today's computer. (Tested with: http://www.vanheusden.com/DeepBrutePos/ ) Also, they did not negotiate a time limit for the moves... A match with a computer is pretty much meaningless when the computer can spend an eternity thinking a move.