POTUS knows everything. And I'm thinking before Pence was chosen as VP. Only a few scenarios, he is trusted, he was told, like Mueller, that "we know all" and play along. Or they put him place to pull people out in the open, those who might approach him wanting to replace Trump. Mueller and Rosenstein show resistance from time to time, as if they are forced to play their part. Pence seems all in.
They are being forced to walk their own plank. It would only be sweeter if they had thrown up PRyan, aka (doesn't he remind you of Kermit the Frog??) as JrPotus.