Fan disc that fail are bad enough. Back, I have seen the result of a front bearing internal fire and severing of both the main shaft but also the "fail-safe" shaft releasing the entire fan disc assembly. It was the 22B version (early model) of the RB-211 and the entire assembly marched forward. Being in the Nbr. 2 position of an L-1011 it ate out the S-Duct section, dinged the top of the horizontal stabilizer box below it and came apart just before entering the rear pressure bulkhead. Portside hole in fuselage side was big enough to walk through. Severed three of the four hydraulic systems, fourth had damaged tubing but fortunately was not holed. Eventually, an AD required a system to be installed to detect the first movement of a failing front locator bearing. That essentially, due top cost, ended the 22B engine and sped the retirement of all the L-1011-1 models.
I actually witnessed a disc from a CF6-50 engine roll at very high velocity across JFK airport and end at the then Pan Am ground equipment shop. Came out of an Overseas National DC10-30 on takeoff roll. It aborted, came to a stop and I saw the best evacuation of a burning aiurcraft ever. All aboard were ONA personnel going to support Hah flights. Unfortunately, the fire totally destroyed the aircraft in spite of the efforts of the JFK PONYA firefighters.
Don't believe any protection will prevent whole discs from coming out. Aircraft survival will depend on which way it goes.