"Since I just told you I wasn't saying knowledge like this wouldn't help, yes, you're wrong," John stated bluntly. "I'm not saying don't prepare. I'm saying be smart about it. Look, I have no idea who G.I. Joe is or what he has to do with NASA, but there's another part to what he said: knowing is half the battle. Survival isn't about what you know, but how you think. Derek and I come from the same world, but different circumstances. There were years between my father's death and when Derek was able to join us, years in which we lived on different fronts, in different circumstances. So, our specific knowledge is different. But, we share a similar way of thinking because that's what survival is: a way of thinking."
He crossed over to where she sat and squatted down in front of her, elbows resting on his knees as he spoke. "The thing is, you can't prepare for everything. It's impossible. It's like chess," he explained. "You want to be able to think three moves ahead in order to stay on top of your opponent. But, if you start trying to see five, ten, twenty moves ahead, there are too many permutations and you're left guessing more than actually planning. Start at the beginning. Take what Derek's teaching you and expand on it. Consider what other applications the things he's teaching you can have. Go through the things in your possession and consider every use you can put them too. These are the things you're taking with you. The things you're as close to guaranteed to have available as you'll get. Then you think about what things you don't have but that could be useful when combined with what you do have. Then, what you could use with those. Then, and only then, if you have time and resources, do you start thinking of things you don't have, may or may not get, and don't serve any purpose in conjunction with what you have.
"It's like the tech. You're thinking like someone who's used to having things at her disposal. And that's fine. It's good...if you're living in a world where it's a given you can get it." And he wasn't going to ask what a tardis was. It was either something in her world or another pop culture reference he'd never get. "But, when we don't know what we'll encounter, tying the machine's operation to the tenuous availability of a laptop would be ill-advised. And if we have a working machine, the research is done. Mission accomplished. There's nothing left to do."