We can only HOPE he was rattled by this burgeoning scandal, but, I think he was just pissed that his regular Wednesday at the White House Party Night was postponed—he was going through withdrawal.
Maybe it was because people weren't fainting in the aisles and giving him instant applause and hooping gratification. He feeds on that.
He isn't used to being timed out on his remarks or having someone say to his face that he is....not speaking accurately.
He was not in control and it freaked him out.