1 Young Jamie: We're never going to meet our own grandfathers wandering around the base. They'll be locked away in a secure lab somewhere.
2 Young Adam: What do you suggest?
2 Young Jamie: Let's go into town and hang out in a local bar.
3 Young Adam: So we can meet our own grandmothers and try to become our own grandfathers?!
4 Young Jamie: I was going to say so we can think about our options.
4 Young Adam: I've already thought about them.

He obviously hasn't thought about it long enough.

Don't think about it too hard yourself. It is slightly disturbing, but I'm afraid this sort of thing is virtually inevitable if you start mucking about with time machines.