While the corrective action relative to the oil fire (faulty pipe manufacture, etc.) is entirely appropriate, I hope that R-R doesn't stop there.
The fact that the T900 engine cannot survive a IP shaft disconnect is really disturbing to the turbomachinery folks I see often. I give you the RB211/744 failure
QF74, 31 Aug 2010, KSFO - the shaft broke, the IPT oversped, but it shed its blades before reaching burst speed. An uncontained failure (escaped turbine blade fragments), but with considerably less airframe damage.
A couple of aggravating circumstances here
It may not have been just a pure overspeed failure. Given the coloration of the disk there
may have been abnormally hot temperatures at the bore weakening it further than the shed speed of the blades.
The uniqueness of the IP module area may have prevented the massive tangling between blade airfoils and stator vane airfoils.
nevertheless the first priority corrective action should be against the massive oil leak that caused the shaft attachment failure in the first place.