if there was a bang, all the oil left and it started ratteling it sounds like a ROD left the building.
they don't allways punch gaping big holes in block but can snap the intermediate shaft and or just crack the block or sump.
and they'll drive when blown up. i drove a 16v 4 miles on 3 cyls after a rod went out through the side, it took the oil pump, intermediate shaft and all the oil with it as well. it even was shunted around on the drive under its own power till k took the motor out