Centreline closure, if my memory serves me well, was caused by the ingestion of supercooled water droplets which caused the compressor casing to contract and touch the blades.
The result could be blades breaking and passing through the engine to the turbine causing it to break up in turn.
With the other engine and vital ancillaries like hydraulic pumps and generators so close the outcome is no difficult to imagine.
I think the fix involved some sort of abrasive material being fixed to the compressor casing so the blades would grind down rather than break off.
Hairy, the engines at idle rpm had weird undulating sort of low pitched moan that was very penetrating.