Shame VS Guilt!!
I believe Narcissists can feel shame which can be a subset of guilt.
This shame however is more manageable than guilt since it can be obscured by projecting blame on the innocent.
A reaction to shame can trigger an avalanche of lies, rationalisations and retribution.
Someone so perfect couldn’t possibly be responsible for your pain.
Guilt however implies a knowledge of responsibility and empathy towards the aggrieved which a person who has spent a lifetime in self justification is not capable of.
Those I have known to be untrue to themselves had spent an enormous amount of time erasing any accountability in order to remain faultless.
This included smearing their perceived enemies or targets of their abuse, rewriting history to insure they were seen as the hero and ruthlessly expunging from their life anyone who suspected the truth even at great cost to themselves.
So the emergence of guilt is probably a trigger that sets every twisted primeval defence mechanism in motion.
This happens as reflex the same as how we might flinch when someone throws a punch and the threat must be destroyed.
Much like a person who doesn’t like crawly things will cut the head off a harmless garden snake.
No Guilt just Disposal.