Ellipses are used differently in academic or non-fiction writing and narrative fiction.
In academic non-fiction, ellipses indicate that the author has omitted part of the citation. In narrative fiction an ellipsis indicates a pause in spoken language. (I'll come back to that.)
Other options for indicating pauses or breaks in spoken language in narrative fiction are the em-dash ("—"), but also colons and full stops.
A speaker hesitates briefly, maybe because he is trying to think of the best word:
(This is very similar to a "voiced pause" filled with "err" or "hmm" or "um":
That was, um, unfortunate.)
A speaker is interrupted and does not finish his sentence:
A speaker pronounces each word separately (imagine him beating his fist on the table with every word):
That. Was. Unacceptable!
A speaker pronounces each syllable separately:
The word is un-for-tu-nate, not unfornutate.
A speaker makes a brief pause, emphasizing the first word:
That, was unfortunate.
And so on.
Now, I said – and you read – that pauses are made in spoken language. Pauses in written language take the form of a line of whitespace between paragraphs or a chapter break, both of which often indicate that some time has passed:
... and went to bed.
In the morning ...
But spoken language must not necessarily be limited to dialoge enclosed in quotation marks. Some narrative fiction, for example, is written in a style mimicking spoken language, giving the impression that the narrator is not writing the tale, but verbally relating it to an audience. Often there is a framing narrative that explains who is telling the story to whom and under which circumstances, but often this is only implied within the narrative itself.
Much of first person narration is of this type, where the narrator is not telling a tale with a detached, unemotional voice, but rather he or she is emotionally involved and sometimes even exclaims in surprise or – hesitates to continue (as I just did, with the en-dash, for effect).
Here is a quick made up example, with two pauses in the narration (signified by an ellipsis and an en-dash, respectively):
Oh my God! Ben!
"H-hey, B-Ben," I stammered. I felt...excited, I realized in surprise. Since when was I excited about – Ben?
It is certainly not the best writing, but I am sure you have encountered similar pauses and breaks in your reading. They are especially common in first person Young Adult fiction.
Ellipses can appear in the narration outside of dialoge, if the narration is supposed to represent spoken language.
In the example you give in your question, the ellipsis is perfectly fine, in my opinion, and gives the (short) text an appearance of being thought or said by a person (of whom we will learn more in the course of the book), instead of neutrally reporting events in the manner of a recording machine.
I did not follow your link to check if you criticism would still stand with this information, because that was not part of your question and did not appear relevant to answering it.