Jo wasn't entirely sure about taking advice from someone who'd admitted he'd lied. And she was fairly sure she'd notice if someone was particularly jeopardy-friendly. But she also wasn't going to dismiss his advice out of hand. "I don't know..." she began, but drifted off as she saw something she wasn't expecting to.

She stopped walking when she saw it and looked over at 'Jack', her eyes wide. "Doctor?" she asked softly, thinking of all the people who could have a TARDIS that weren't the Doctor.