Ten doesn't blame her for being cautious after a war. But what happened exactly? Scanning for what? Ki? What are Ki?

Pretending to know who she is would probably be a good idea, now, "Really? Well, I can't believe I'm getting to meet you." The Doctor offers a professional handshake and wide smile.

On the way back to the TARDIS, Ten hopes that a Telephone Booth isn't something strange here.