I got this image of an oil tanker that deliberately spilled it's oil all in the ocean and pristine sand. All this toxic waste was meant to decimate the beautiful sea and land. Everything in the ocean was meant to be destroyed while washing ashore it's remains.
This is what the narc is doing when they do their grand finale discard. They want you to gulp down their toxicity to the last end while everything in your being is decimated to the core. They are so jealous of your beautiful soul that they want to contaminate it before they leave, like an alpha dog relieving itself all over your carpet. They want you to remember that they never approved of you and all you deserve is there last encore.
Even their performance is all about them, taking away the privilege of you discarding them. What are they running away from? Your courageous and beautiful heart that is full of love. They can't stand looking at wholeness and anything admirable. So they have a need to dump their toxic waste to cover all that goodness in you so they don't have to look at it anymore. The narc is a sore loser and if the competition gets to fierce and they can no longer dwindle you down to nothingness, they will leave.