I believe he knows he is in deep water as Mueller knows full well he failed to accomplish the assigned mission - to uncover Russian collusion. There is solid evidence of Russian collusion only it wasn’t with Trump or the Republican campaign. It was Russian collusion with H. Clinton and Obama. Mueller failed to investigate that fact and thereby failed in his job as Special Counsel. Maybe he fears his failure will be publicized and his name will go down the gutter of history. This has monumental consequences.
Monumental is the word.
I don’t think these idiot Democrats and their media lackeys have any idea how much they damage themselves with this two-year giant lying exercise trying to turn Trump into Dick Nixon