Martha / Jacob
Trust me, I know how strange it all sounds. I've tried to explain all this to my family and my ex-fiance. Does it help if I call them "Macra" instead of giant crustaceans? It probably doesn't, does it.
I... don't know, honestly. I suppose it was because I was one of the few people not having a panic attack over being on the moon, and I wanted to find out what was going on. That's what the Doctor does. He ends up in the right place at the right time and he sorts out what's happening, and fixes it. It's what I wanted to do, so I helped him. And then he offered me a trip back in time, and... before I knew it, I was traveling with him. I just sort of got caught up in it all, in the Doctor's whirlwind, until my family also got caught in it, and then [...] I left. He's still traveling, though, which is good. The universe - universes - need him.
See? It's not so bad. Adventuring around, making maps. Helping people avoid getting lost. That's a very worthy purpose. Must be hard to do that in the snow, though.
Oh... yes. A telephone, only a bit more modern than the sort your friend Bell invented. Or will invent, in another few years, rather. You can see it, if you want. The Time Lords have incredible technology, beyond anything you or I could imagine. Or, well, we could imagine it, but we wouldn't be able to get it to work. I've only had the smallest glimpse of what they can do, I'm sure.
[...] I'll be alright. I have friends here, and plenty of work to do. I'm sure I'll make it back eventually.