>It may not generally be known but the armour plating is designed to " contain" the N1 or Fan section of the engine in the event of Foreign Object Damage resulting in break up of the Fan blades.
I am personally not aware of any engine which is currently designed to contain the N2 or high compression stages of the engine if they should subsequently break up.
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The requirement is to ensure that the outcome of a single blade release (from any cause) does not burst (become uncontained) the engine casing, no mater what stage (fan, compressor or turbine). There is no requirement, nor am I aware of any claims, to contain anything other than blades (like rotor disks).
History has shown that debris still exits the engine by going forward (through aircraft inlet cowls) or aft out of the tailpipe.