(A side-story in the 'Matt's Ghost' series.)
Somewhere along the line yesterday, Sylv picked up a temporal echo. It's barely perceptible - a sense of awareness, of someone looking around, taking the world in. Even so, Sylv knows it's a girl, knows her name's Raine. For some reason, he's reminded of Lady Christina, in David's class, that sense of criminality and style. (It's certainly more than they can get from the echo that's been following Paul around, which seems to lack even the vaguest sense of identity.)
Sylv has the strangest feeling in Raine's presence; the feeling that what's happening now could have happened, /would/ have happened, a long time ago, had events not conspired against it. /What/ events, Sylv's not sure.
Time Lords are as susceptible as anyone else to wondering what might have happened, and, much like anyone else, they eventually return to the world at hand, put the possibilities out of mind.
But somehow, what was a lost potential, a forgotten possibility, has returned, is becoming a reality. He's about to find out what it was like on the road not taken.
It's a rare chance, Sylv knows, and so long as he remembers that, keeps it in mind, it'll be one worth exploring, too.
[To explain: Big Finish's second 'Lost Stories' series is set to include stories from the unmade 1990 season, featuring the new companion they planned to introduce, Raine, who happens to be a safecracker.
[The echo following Paul around is his new Big Finish companion, whose identity is set to be revealed in the upcoming 'Situation Vacant'.]
Disclaimer: 'Doctor Who' is the BBC's. Raine is probably Big Finish's.