Interesting, I never thought of it that way. Maybe because it was billed as the start of a series, so at the time I read it I expected a next book.
A Tale of Two Cities was a standalone.
In any case its what we're left with because she'll likely never write any more books. At the time I just assumed she planned to resolve the situation in the next novel. Since there was never a resolution I always sort of imagined, like you said, oh well he just died. But I always thought she was just setting up the next book in the series.