There were so many directions Martha could go with this conversation. It took her a moment to respond, and when she did, it was perhaps not what Reid would have expected.
"You told me once that I'm part of a fictional programme in your world. A show that follows the Doctor's travels. So tell me, has he ever rambled on about the wibbly-wobbliness of time during an episode? He harps on it regularly, so I imagine it's shown up at least once. Anyway, the thing about time is that most things aren't set in stone. Things can change."
Her eyes betray her confidence in the statement though. There's a sadness behind them that calls out the lie she's been telling herself since that day.