Excellent write-up, Phaser Two! But I would say that the premise is the key item that needs to be "fixed" for this episode to work. The concept of antimatter dates back to the 1880s, with the modern version dating to a Dirac paper in 1928. The first I heard of it in my armchair physics reading was the idea that the Big Bang created a universe with half-and-half kinds of matter, where entire galaxies might be "CT" (contra-terrene, another term I picked up from sci-fi).
Thanks! I enjoyed writing it.

Yeah, you're right about the physics. In my sci-fi reading days as a kid, inspired by TOS, I tended to concentrate on the stuff that involved, let's say, moral or humanistic issues rather than hard science—so more of the Heinlein/Clarke/Asimov/Bradbury/Burroughs/Wells pantheon that was "soft" sci-fi (rather than say Verne or anything from the aforementioned authors that wasn't). I even read back to Mary Shelley and Poe. THEN I started higher education, and a conflict was created, because pretty soon, I sort of knew better than to accept some of this stuff. But I still kept a separation between what I liked to see or read and how I analyzed it. For me, if I try to explain everything away that's happening on screen, it just sort of makes my head hurt and ruins the fun to some extent. Plus, I'm not one who often rules things out as impossible.
But you have a great point. I think they were going for vacuum theory here, maybe? It's bad. When I said the premise was decent or whatever I claimed above, I meant that the E suddenly getting caught up right at ground zero of such a significant phenomenon was interesting. But the execution was horrible—and, well, they did the same "crew in the center of a mindbending, all-important event" the very next ep by airdate, with juuuuuust slightly better results.
The premise is not unique to Trek, but it is kind of uniquely ludicrous. If you touch another version of yourself from another universe you will die, or things near you will be destroyed, or the universe will end. Really? How does the local universe, or the multiverse, know that two objects are counterparts of each other? Lazarus' body is not one single thing with a unique ID that's registered in some kind of multicosmic database; it's a collection of gazillions of cells that have been getting added to, removed from, and changed in, that body for its entire life. How many cells have to match? If the tipmost cell in my left ring finger was made from a baked potato in one universe and a Wendy's double in another, are they the same cell? How does the universe know? What about the components within those cells? How many atoms have to be the "same" from both universes? How many sub-atomic particles? There's literally no possible mechanism to enforce this mutual destruction other than "bad writing magic."
And if there was a mechanism for this, how risky would it be to deliberately bring matter and anti-matter into collision with each other to propel starships?
Right? They use this down in the engine rooms, but suddenly it's really lethal. *Really* lethal. Apparently the counterparts have to meet for it to be a problem, and I sort of get the impression they can't meet, but Bad Lazarus worked around that. Seems like that would have been threatened before. At no time do you get the impression that this lunatic finally had the wherewithal to be the first to figure it all out.
The much worse problem with the episode is how stupid the crew is at every turn. It all culminates with two men being consigned to an existential hell inside a spinning newspaper for the rest of all eternity


The spinning newspaper!!! (And yeah, the crew is dumb; Kirk and Spock take something like 15-20 minutes of dialogue to hash out that it's two guys. McCoy should have had his medical license revoked, and between this and "Space Seed," Kirk should have been removed from charge of anything larger than a toy bathtub boat.)
Spock forgot he can put people to sleep with his fingertips. He was standing there on the planet, literally right behind an antagonist who was grappling with Kirk, and the finest first officer in the fleet did nothing? Literally, all he had to do was neck-pinch the "bad" Lazarus and then that one could have been tossed into the magnetic corridor — alone — and his bubbleship then vaporized to lock it forever, or he could have been humanely euthanized for the welfare of two entire universes, or he could have been mindwiped at Elba II like Captain Garth, and the "good" Lazarus could then have lived out his kind, gentle life in peace, with plenty of free time to see a barber about that horrible beard.
I think they both have to get in that newspaper corridor together or the solution doesn't work, and if they didn't both go in there, the destructive events of blurry star graphics appearing at random and generating turbulence and wind (??) would continue to screw up everyone's weekend. Ingalls didn’t explain any of this, of course.
But that whole fight is ridiculous. Not just Spock but the phaser two (yay)-sporting guards stay back on their commander's vague instructions while Kirk eventually overpowers Lazarus, and it's poorly blocked and edited. Brown, though, gave a good accounting of himself, picking up Shatner's probably 165-170 pounds almost as easily as Ted Cassidy.
Oof. Still glad I watched it, though.