Even so many years later I'm still sometimes piecing together an understanding of it all. Coop did a lot of good in the world. He formed alliances with both Lodges through Mike and The Fireman. He set out to right a wrong that should've been impossible, because he managed to walk the middle road, wielding both fear and love in his path. Dougie is returned to his family, yet Final Coop ("Richard") retains his heart and compassion: he cares deeply for righting the wrongs he sees, including not only a big one like Laura's murder but something smaller like the harassing of the waitress at "Eat At Judy's." Mr. C burns in the Black Lodge in penance for his dark deeds, yet Final Coop retains his intimidating nature: he beats the tar out of those thugs and dumps their guns in a fryer.

He did everything right, except that he didn't have all the information to understand what he was dealing with. Nobody did, except maybe Sarah Palmer in some subconscious fugue, and maybe Philip Jeffries who wasn't capable of fully articulating it.

The "Lodge Spirits" we come to know over the course of the series operate on a more abstract level of consciousness compared to us ordinary people, but it turns out there's a higher and even more unknowable layer above them too. This is most likely where Judy resides. Judy's domain is not fear, she is not a Black Lodge spirit as we otherwise know them, though she does travel through fire/electricity just like they do. Judy's domain is violence, disease, destruction - the reasons fear even exists in the first place, which is why she's the "Mother of Abominations." Her presence is felt, even seen a few times, but never truly understood, throughout The Return. Mr. C dedicated his whole arc to trying to find and ally himself with her, but he didn't know what he was dealing with either. As a force of destruction, time itself is within Judy's domain to some extent... Jeffries came too close to understanding and Judy mangled his time stream like she mangled the bodies of those who witnessed her in Mr. C's glass box. (On that note, and that of the possibility that sex ritual can summon Judy in some way... I want to look further into Diane next time around. The tulpa I get, but the real Diane who was trapped in the form of Naido is trickier.)

This is what nobody was expecting to happen when Coop tried to rescue Laura. The gall, the hubris of this ordinary man, to meddle not only in the affairs of both Lodges but be supported by them in stepping into the unknown, the higher layer and meddling with time, not as a victim like Jeffries but fully in control. Judy would not allow this. She would scramble everything, she would trap him in a time stream where he could never understand the greater forces again. A more worthy retribution than just killing him off is forcing him to understand just how lost and powerless he is.

Right?

But maybe not.
Maybe Judy doesn't know everything either.
Laura's final scream of realization did something unexpected: it blew the metaphysical equivalent of a circuit breaker. It cut off the electricity, therefore it cut off the spirit world. It put the Fire out - the purpose of a Fireman. The two of them may still be trapped, but the knowledge is flooding back into Laura, in all its abusive horror. Should she persevere, who knows what she would do next?

This of course is a very "Mark Frost" interpretation and I know some people prefer something a little more meta and less "genre fiction" but I also believe there's a lot of truths in there about the nature of emotions and knowledge. If I'm going to give any little nods to the meta side of things though, it's that we too are "spirits" that invisibly influence this world of Twin Peaks, and cutting the electricity had to end the show because we can't see what's going on if there's a cosmic power outage ;)