 Which isn't something the guard did?
There is one fact no sane man can quarrel with ... You will, you know, so why quibble about it? At least, you always have ... or do ... or will. Some kind of telepathy seems to work between two of the same people. Yes, it'll be pretty obvious it must be a time machine. 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. Doesn't hurt, and when you pull your arm back, you're still sound and uninjured. "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. If you don't, it's a good way of going crazy. Maybe there is no machine, and it's just easier for us to imagine it. That means you either carry a small time field with you, or you are catching a small increment of time from the main field. Maybe the machine has a gravity field built in, or maybe the time that makes your watch run is responsible for gravity. "This is like the things they wear in this century, as near as I can remember it, and I should be able to pass fairly well. There's no feeling of acceleration—some kind of false gravity they use in the future.
 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