I might have expected it
There is a point at which he finally gives up on people -- even his oldest friends, his oldest enemies. Mortal sin by intent and by commission, and so many times.
Murderer, a recent part of him says coldly. Prattling jackanapes, an older part adds. Old friend, whisper the shadows of his most distant past.
Of all the things that Gallifrey could leave to the Universe, the Master is one of the worst.
Yet still, looking out the starry darkness beyond the viewscreen, he remembers a sallow bearded face, burning eyes, quick gloved hands; and he thinks, He'll be back.