No Omniscient Narrator

"Now the story splits again, three ways this time. I'll have to reconstruct two of them from what information came to me later, most of it brokenly, and the best guesses I can make. Nor may I say much about my own experiences. They're branded on my memory, but I  gave my word of honor I'd keep certain things secret."
-Poul Anderson, Operation Luna (New York, 2000), Chapter 37, p. 332.

This is the opening paragraph of Chapter 37. Not only is there no omniscient third person narration here but the first person narrator openly admits his limitations. First person narration always opens the possibility that a sequel will contradict the narrator. Thus, Watson wrote that there were no handholds by which Holmes could have climbed up from the place on the footpath at Reichenbach where he fought Moriarty. Holmes returns and says that there were. Even without a first person narration, in Ian Fleming's eleventh James Bond novel, M informs readers of The Times that the friend and colleague of Commander Bond who had popularized his adventures was not prosecuted under the Official Secrets Act only because of his many inaccuracies - thus neatly explaining Fleming's inconsistencies and cutting ten years off Bond's life!

In the case of Anderson's Steve Matuchek:

the information that came to him later might have been inaccurate;
the story that he reconstructed from it could also be inaccurate;
his guesses could be wrong;
another participant in his later experiences might not be bound by the same oath of secrecy.

Thus, here is scope for a sequel that would not only add to but also contradict Matuchek's account. But his account would still stand as his account, to be read before the better informed sequel. More could be done with alternative points of view that most authors or readers realize.