Anything that comes loose will be blown out the back of the engine so is uncontained in that limited sense. The containment design problem refers to loss of a fan blade. In that event the fan case is designed to contain the blade so that it does not fly sideways and penetrate the cabin for example. But such a failure produces a lot of debris that will escape to the environment through the back of the engine.
Completely ignoring the issue at hand, namely a turbine disk failure. However, these are invariably uncontained as the energy involved is too large to be able to effectively contain it.
A photo shown taken from a passenger shows some debris has shot through the wing less than twelve inches in front of the wing front spar. Behind the front spar is the fuel tank! I'm tipping that if a piece of hot turbine had gone though the wing tank it would have made the Air France Concorde disaster look like a fairly small accident.
It could be that the passengers are still alive by the grace of god... Or it could be that the engine was positioned so that a turbine disk failure would not penetrate the fuel tanks. I know the latter isn't as exciting, but it's got the advantage of factual accuracy.