How, can anyone explain how M's office can change in one day too (it's supposed to happen a short while after CR).
My guess is, that it was just some sort of a operation control room, with a desk set for M. An office away from her usual office.
In any case, it didn't bug me a one bit. Even though when I saw the trailers, this was one was one of the biggest how/when deals I had regarding this movie.