I think what Dr. Mauer meant was leaving would mean killing all 25, 26 if you count Ms. Casey, of Gemma's innies. In a weird way Dr. Mauer was like those innies' father but also like...wanted to find love with at least one of them?
I'm going to kind of continue the conversation
@Sombastate and I were having by elaborating on my thinking. My interpretation of the way the testing floor worked is there's a difference between the Severance doors on the testing floor and those on the severed floor/birthing cabin. I think each of the doors MDR helped prepare are specifically and separately coded to unlock a part of Gemma's chip for a different innie that can only exist on the testing floor. Like if Gemma went into the birthing cabin from the finale, she would revert to Ms. Casey, not one of her 25 other innies (or all of them at once which would probably overload her brain and kill her). To put it a different way, I think innies like Ms. Casey, Mark S., Helly, etc. are what could be considered generation 1 innies, while Gemma's innies are generation 2, and generation 2 is still in the development stage and can only exist on the testing floor. I think that's what Dr. Mauer means. If they take Gemma from the testing floor and she never returns, all those innies effectively die.
From there, whether the end goal was having Gemma's testing floor innies replicated for the anti pain/trauma/discomfort Severance chip the show was implying was the purpose of the experiments so those innies could serve as generic blank slates to be be the ones to endure the pain and suffering of the general public, I don't know. Part of me thinks that's implausible since an innie is still a construct of an individual's own psychological wiring. I would think that overwriting 25 versions of another person into a different person's brain would result in psychological chaos if not driving people to sheer insanity. But I don't know how else we were supposed to interpret Dr. Mauer telling Gemma that "you will see the world again and the world will see you"
But the point may be moot if they can't get Gemma and her chip back.
In any case, maybe there's a double meaning and he's thinking long term that if Gemma and her story are leveraged to destroy Lumon, it would mean the end of the lives of the innies, the way i!Mark speculated. The thing is, we have two seasons of this show not quite being Game of Thrones, as in, while bad things happen to these characters it's never quite as tragic as the worst possible outcome (e.g. Ned's death, the Red Wedding, Tyrion losing trial by combat, etc.)
I think bad things are still to come for the innies and outies and there will be continued struggle and conflict with Lumon, but I feel like Lumon mass wiping the innies is a bit too dark an outcome for this show. Maybe it happens as the season 3 big finale moment, but my expectation is that the eventual compromise solution is that the good guys will find a way to reintegrate everyone who severed. In a way, that's a loss for the innies because they lose their unique and separate identities and autonomy over their separate lives. But if an innie decides to live in perpetuity as their innie selves, then that just kills their outies and I can't see this show taking the moral stance that outies deserve to die as penance for creating the innies in the first place. Reintegration was introduced as a concept for a reason and I think that's the endgame. Convincing innies and outies alike that Severed existence is not feasible and that they should reintegrate to make their two halves whole.
