As read elsewhere, getting wind of what the Doctor was about to do with the moment, Rassilon and the High council buggered into their own time locked area, probably with the Capitol itself. I'm assuming Arcadia becomes the new Capitol if/when he finds things. Although, that would bugger up the Eye of Harmony and other stuff. Rebuilding that stuff would be tricky... unless the Doctor happened to know where the Hand of Omega was hidden...

Hmmm....