 Which isn't something the guard did?
There is one fact no sane man can quarrel with ... But some men aren't sane; thus it isn't always so! I'm not your father's ghost, even if I do look a bit like him. You will, you know, so why quibble about it? At least, you always have ... or do ... or will. And don't look at the machine out there too long—until you get used to it, you'll find it's hard on the eyes, trying to follow where the vanes go. You're wondering whether to give me a drink, as I remember it. And naturally, since we have the same tastes, you can make the same for me as you're having. And you can look at the revenue stamp date, if you still doubt my story. It's a real wrench when a man meets himself for the first time. Some kind of telepathy seems to work between two of the same people. So let's begin when you get up in half an hour and come out with me. Yes, it'll be pretty obvious it must be a time machine. You've seen it, just a small little cage with two seats, a luggage compartment, and a few buttons on a dash. You'll be puzzling over what I'll tell you, and you'll be getting used to the idea that you are the man who makes atomic power practical. You won't exactly believe it, but you'll want to go along. So I cut off your questions, and get you inside. You can see a sort of foggy nothing surrounding the cockpit; it is probably the field that prevents passage through time from affecting us. You start to say something, but by then I'm pressing a black button, and everything outside will disappear. You are completely outside of time and space, as best you can guess how things are. You can't feel any motion, of course. Doesn't hurt, and when you pull your arm back, you're still sound and uninjured. Then it comes to you slowly that you're actually traveling in time. Then you feel silly, because you'll remember that I said you'd ask that. Well, I asked it after I was told, then I came back and told it to you, and I still can't help answering when you speak. "Maybe it's no dimension—or it might be the fifth; if you're going to skip over the so-called fourth without traveling along it, you'd need a fifth.
 help him carry the atomic generator to the time machine
 help him carry the atomic generator to the time machine  help him find the atomic generator  hand him the patent and other helpful information  give him time to take it out of the building