When petitioners die off-plane

I've always thought that the petitioner became one with that plane, as well.  On its home plane, this was a comfortable merging, because most of the petitioner's spirit was compatible with that plane's alignment and attitudes, and so the petitioner survives in some eternal abstract form as part of the plane's strength.  When it happens naturally, it's because existence in the plane has slowly refined all aspects of the petitioner's spirit to the point where there are no noncompatible features remaining, and the lines between it and the plane just vanish.  Imagine the petitioner as a lamp that has been tuning its color; once it perfectly matches the light all around, you can't see it anymore, but it's still strengthening the light you see.   When the petitioner dies by violence on his home plane, most of himself survives; the few remaining incompatible bits react interferentially with the plane, and for all practical purposes cease to exist along with the tiniest portion of the plane's strength.

When the petitioner dies off-plane, most of his personality doesn't match the plane, so as it merges most of it fights the plane and sets up such an interference, cancelling out some of the local energies.  Only those parts of himself that match the local plane, imperfect parts he would rather have been rid of in the first place, survive and merge with the local plane.  What's eternally left of him are the parts he doesn't like anyway.  A dreadful fate, unless he's particularly militantly-minded: a squadron of dwarven einheriar marching from Arcadia to Acheron might consider their sacrifice worth it to weaken Acheron's evil (though we, secretly, know their gods save them from such a fate).