I've experienced many "non-linear" events in engine tests. They are always exciting.
And I defy any pax not halfpissed, upon witnessing an uncontained failure outside his window, to refrain from calling it an "explosion".
And per the certification rules, uncontained failures are specified as/required to be "extremely rare", because the energy in the released fragments can be very harmful. The QF A380 is the recent poster child, but not the worst case. The 1989 Sioux City UAL DC-10 may be the worst domestic case.