Here's why I suspect Barr deliberately shut Mueller down before he was finished:

[JayhawkSD]

48. "...a bunch of Russians (who will never be prosecuted here)"

You should check your facts. They are here, in court, in a trial being delayed not by the Russians, but by the prosecution.

The Russians showed up to defend themselves in court and the prosecution tried to prevent them by claiming that they, the prosecution, had "not been able to serve them." That service, the judge pointed out, was merely formal notice that they were required to appear in court and, he pointed out, they were presently in court, so he was unable to understand why the prosecution was objecting.

The Russians then asked for "discovery," which is their right. This is the presentation to them of the evidence which the prosecution has gathered against them. The prosecution demurred, saying that it was "not yet ready" to present that evidence. The judge was even less sympathetic than he had been with the prosecution's efforts to delay beginning of the trial. He wanted to know why, if they did not have their shit together, did they come to trial in the first place.

The evidence against the Russians has still not been presented to them, and the case is in danger of being thrown out of court.