Mueller is tipping off the media so that the cameras will be rolling when FBI agents make the arrest, put the subject against a wall and handcuff him.
The reason the indictment is sealed is so that the subject doesn’t get advance knowledge such that he and his lawyer come voluntarily and quietly to surrender and be arraigned and deprive Mueller and the Democrats of their television moment.
Correct, they have an election in VA coming up and they need something to bash republicans with, not to mention get the media worked up in a frenzy.
If it's Manafort, I'd like to see him buy OJ's old white Bronco and lead federal marshals on a slow-speed chase.