Oiljob, wouldn't simply drilling through it and extracting the debris work?  It would be like drilling out a snapped screw in a tapped hole only 4000' down; LOL!   Drill through the center of the snapped screw and the outer part of the screw collapses.  Then clean the bore with a new drill bit.  On the other hand if it was this simple then I assume they would have tried this method.  Are they trying to save the packer for reuse or repair if necessary?