It did NOT catch fire!
The IP and LP turbine has failed. The 30 ft??!! (or 30 mile
) flames or whatever were the result of the surging and subsequent turbine failure.
The fire bottle . . . . YES only ONE was used, would appear to have been precautionary and no disc failed. The HPT appears on the face to be intact.
All the same it is an interesting failure of what is normally a very robust engine.