Re: A thought on regenerations (spoilers for "Night/Day of the Doctor"
Well the Curator is indeed a future Doctor as it's been suggested, finding Gallifrey is in his past from his(the Curator's) point of view. In any event I don't know why he need to sense them currently nor do I understand why he put them in a place he couldn't retrive them from.
The greatest science fiction series of all time is
Doctor Who! And I'll take you all on, one-by-one
or all in a bunch to back it up!"
--- Harlan Ellison, from his introduction
to the PINNACLE series of Doctor Who books