We just sort of... find people. If we come across someone, we invite them into the group. It's backfired, occasionally. We try and see the best in people though. I think most of them need all the help they can get.

I'm not sure I believe all this stuff about Cybermen and invasions to be honest. And even if it's all true, well... what are we supposed to do about it?

We find the weakest structural point and blow it up, of course. We have to hope we have enough explosives for it. That's why we brought them, after all.