Maybe they are worried that Comey is leaning towards recommending indictment. So, by Hlliary campaigning with Obama, Comey might be pushed towards the “correct” conclusion.
She is going to be cleared today so get ready for it.
Don’t forget that Hillary has indicated that she will keep Lynch on as AG. So Comey knows that there is a good chance his boss, Lynch, will be around after the elections if Hillary wins. I wonder how that fits into the equation.