This all fits.
Everybody assumes Sessions was forced out, but what if that is not the case? It is entirely possible (and logical) that Sessions' entire function may have been to quietly gather evidence behind the scenes (away from media scrutiny, which would have slowed him down or stopped him) all in preparation for this day.
NONE of us know if this is true, but it certainly is POSSIBLE.
If it is true, Sessions will soon make the transition from inept, villainous traitor to selfless unsung hero for his personal sacrifice.
Stay tuned–time will tell.