I think this is the most likely explanation of what is afoot here. And I do think reports of pressure from within the agency are credible. The Democrats are playing a dangerous game by pressing Comey to be more substantive. He may feel forced to expand on the nature of the new evidence, and chances are it is not something they will like to hear.
Comey is dead professionally and politically. He is trying not to be dead Physically. Big indictments with a big net that catches the main players and makes the middlemen run for cover is his only chance. He is probably looking for his own Ecuadoran Embassy Suite.
I wish Comey would announce that he is considering honoring the democrats’ request and releasing to the publica ALL OF THE EMAILS they recently found. It would be hilarious watching the liberals backtrack.