"no, no . Not at all. Infact, there was once a time when it was quite common." The Doctor says conversationally.

"Sadly though, the race that could do it Safely has mostly died out. Apart from me. I'm the only one left. And you need at least two." he explains easily, as though being the last of your kind was a Perfectly normal conversation topic. Perhaps for him it was. However, if one looked hard enough, they'd see a deep sadness in his eyes. "But maybe someone else has cracked the secret to our success.''