Because we have magical powers from outside the matrix [...].

The AI is vastly more smarter than we and can communicate with us. So it asks us questions which sound innocent to us, but from the answers it can derive a fairly accurate map of how it looks outside the matrix.

It would have to argue that destroying humanity and replacing it with paperclips was a good thing.

The goal of the AI is to have the guard execute the code that would let the AI access the outside world. Arguing with us could be one way to archive this goal. Although i agree it sounds like a unlikely way to succeed. Another possible way would be to write a novel that is so interesting that the guard doesn't put it down and that leaves him in so a confused state that he types in the code, thinking he saves princess Foo from the evil lord Bar.

A super smart AI who wants to reach this goal very badly will likely come up with a whole bunch of other possible ways. Some of which i would never consider even if i spent the next 4 decades thinking about that.

That sounds like more a side effect of reading the same thing "nonstop for 24 hours" than a property of the book [...]

Yes. I am sure any other well written book read for 24 hours would have a similar effect. I think it is likely that a potential guard is at most 2 orders of magnitude less vulnerable to such things than i was at that time. That's not enough against an AI that has 6 orders of magnitude more optimization power.