At the risk of being redundant (again), let me point out that R-R has suffered a few turbine disc disconnects - with different engine models, different containment philosophies, and quite different results.
I give you QF74, 744, RB211 on 30 Aug 2010 (SFO local date):
Qantas QF74 Uncontained Engine Failure - Video & Pics
IPT came disconnected from its shaft and drifted aft due to pneumatic forces in the engine. In this case, the IPT blades DID clash (i.e. first made contact) with LPT stator vanes, thus very rapidly destroying the driving torque to the loose IPT disc. Blade shrapnel penetrated the case and cowl, but the pieces were relatively small so the damage to the airframe was limited.
Contrast this with the QF32, A380, 04 Nov 2010 SIN: T972 suffers IPT disc rupture after shaft disconnect. No rotor/stator airfoil clash, instead the disc became axially restrained against relatively hard/smooth/low friction internal surfaces. Disc continued to accelerate, driven by relatively intact airfoils, until burst speed was reached.
Which, I ask you, was the more successful containment?