Countless examples of uncontained engine failures. Just cause it's part of the certification process doesn't mean it can't happen.
You could probably start a new thread on this topic. I totally agree, there are plenty of examples of uncontained N1 failures (and other stages). I have personally seen one N1 that let go on a 747. The blades existed through the nacelle and peppered the aircraft with shrapnel. In fact one piece would have penetrated the fuselage had the frame not been directly behind the skin where it impacted.
There are also plenty of fools that will blindly deny that uncontained engine failures do occur. I am not suggesting that it happened in this instance, only that it should not ever be disregarded as all engines must pass " Certification tests" in order to gain a type approval certificate.