Here is something to consider.

What if Mueller has something on Trump from his investigation that he is holding close to the vest?

What if Mueller is holding this info back as a blackmail card on Trump in case Trump tries to put Mueller in jail or even fire him from the investigation?

There is something going on with Mueller and I can’t figure out what it is. I don’t know why he has not been fired or why he is not on the list of people that will be taken down with the storm.