First off, the OP is an idiot that knows nothing about ordnance.
The Bomb only has 6,000 pounds of explosives which is not a huge amount. The important thing about the GBU-57 MOB is not the explosives, it it the ability to penetrate 60 meters into the ground before detonating. That is why they call it a "Bunker Buster".
I was in Iraq disposing of about 40-50 thousands pounds of explosives (NEW, not gross weight) every day for a couple of months. We had shallow pits we used for the shots and they only made a crater a couple of meters deep at most. Those shots would have had no effect on a deep military facility.
There wouldn't be any body parts flying around from a detonation deep underground. The only casualties would be the ones that are knowingly sitting on a bullseye. There would be ZERO civilian casualties.