I can’t claim to know anything but the “best fit” IMHO is as follows: one way to deal with Mueller is to get him disbarred for unethical behavior. If one were to do this the court where that disbarment would be heard is exactly this one. This theory could be full of crap for all I know but it could be “tig if brue”. Series.
The leftist reaction to his wrapping up the witch hunt against Flynn and Cohen has shown how "another planet" their (lack of) thinking is.
Disbarment would be handled by whatever Bar Association exists in DC, not by a court.