mentions the Midwest accents
I haven't read the story, but this is a fairly understandable type of author error. Canadian accents in general, excluding Atlantic Canada, tend to be fairly neutral; since the Midwest accent is generally considered to be the "mainstream" American accent, I can see how someone who doesn't know linguistic terminology might use it as a reference point.
In reality, other than the fact that Canadians still use British pronunciations for some words, such as pronouncing the "ei" in either and neither as a long "i" (eye) rather than a long "e" (bee), the accent in BC is basically the same as in Washington and Oregon. For reference, there are eight recognised English Canadian dialects (accents) in total.