"I've met more than one kind of 'Doctor', I can reassure you on that," Nita says, then lets Yuume explain.

"'Standard Dimension'... your world's from a set of five?"

Dimensional sheaths; she hadn't met someone who knew about them in ages, outside of those from her world.

"We'll be on this train longer than that, I'm afraid. So-"

She gestured to the wall behind them.

"How does being a Duel Doctor connect with what you were saying earlier? Might be we have other things in common."