So does that mean that if Sessions un-recuses himself - HE would be the one to request? Otherwise we’d be waiting for RR?
For wrongdoing at the FBI and DOJ, Sessions is not recused. "The Inspector General, who is appointed by the President subject to Senate confirmation, reports to the Attorney General and Congress." Appointment of a special counsel is similar to recusal. The basis for it is "conflict (or appearance of conflict) of interest."
At bottom, the test will be whether the SC is viewed, by the public, as unbiased. It doesn't matter as much who picked the SC, as long as the SC is viewed as unbiased.
Rosenstein's pick of Mueller has failed miserably on that count. At least half the public views Mueller as biased, and not without good reason.
By the way, I'm not saying or speculating that a secret SC has been appointed - just noticing that the regulations anticipate a need and use for such an event, and spell out the basis for doing so.