I read Zeifman on this subject, did you?
Not specifically, but you also have to recognize that the passage of years and situation with respect to the power of the Clintons is something one might consider in their accounts.
If you read Calabrese’s account where he did tell both sides of the story from interviews with more than one person, you can get a sense of what really went on. Whether there an actual letter of firing or a coerced resignation is probably something we’ll not find out.
Regardless, there was more than one person on that staff that didn’t think what she did was ethical - even to the point of lying.