GenDeveloper, You are about spot on with your statement: ''
....... That leakage can lead to a fire, and a softened disk, which then maybe lets its blades go, and departs from the engine.''
What must not be forgotten is the fact that the shafts and bearings are also affected by the extra heat from oil firing which is also a contributory factor to the release of the disc.
With the T1000 disc failure, oil was the culprit again and I believe Boeing have been issued with new guidlines for engine cranking and subsequent running to avoid a repeat performance, but the press release concerning the test cell incident was, from an insider's point of view, interesting to say the least! 