Yeah... I think Rassilon would have been a pretty nummy treat.
If he finds a way to get stabilized and if the drums in his head have finally stopped, his brain may start healing from the insanity the Time Lords caused him... Just think... all those years, from little boy to the drums stopping.
I dunno about you all out there, but hearing the same rhythm incessantly for hundreds of years would really make me all woo-hoo.
Even if it wasn't even thought of more than likely back in the classic series (the drums, anyway, or the Time Lords doing it to him), it was said several times that the Master and the Doctor were very good friends before the Master's mind finally snapped. It brings new light to the way I think of the Master when I watch the classic seasons with Delgado and Ainley.