Show me where the wheel has any interest whatsoever in accelerating? The massive pressure of the exiting HPC gases thrusts the wheel instantly into the LPT Stator. The turbine blades are sheared, and the wheel performs a very rapid eccentric dance out the case, post disintegration.
Sorry, but in the T900 series, the space downstream of the IPT is vacant for quite some distance; The LPT stator (if any **) is well downstream. The IPT blades remained largely intact, providing the "unbalanced torque" (i.e. freewheeling, unloaded) to accelerate the disc to burst speed.
NOTE ** One aerodynamic improvement in the Trent engine is the use of contra-rotating spools. I do not recall positively which ones rotate opposite to others, but I think the IP and LP are opposite. IF this is the case, R-R had the opportunity to ELIMINATE the first stage LPT stator, because the swirl flow upon leaving the IPT accomplishes the same thing. Less weight, less pressure drop, better efficiency, but also the increased opportunity for an IPT overspeed per the present discussion.