It was most likely a coincidence
The crew pulled the CB's thirty six seconds prior to the failure, I think it a little much to write it off as a coincidence, though the report in its conclusions does say the reasons for the acceleration could not be determined conclusively. What the report does say regarding the triggering of the event.
In summary, the catastrophic failure of the No. 3 engine must have been precipitated by a blade tip rub condition which produced the blade exiting sequence. The two most prominent theories as to the initiating mechanism of the blade tip rub, as based on the evidence available, are:
(1) An acceleration of the engine to an abnormally high N1 speed, either by an unrestricted throttle advance by the autothrottle system or a manual throttle advance by the pilot, which created a resonant frequency and subsequent destructive vibratory mode.
(2) A piece of inner acoustic panel from the inlet duct separated from its honeycomb bonding and restricted airflow into the engine resulting in a very rapid fan acceleration and a destructive vibratory mode.