This storyline is my least favorite part of the whole show, because Cobel and Devon, when she's around Cobel, both speak like typical "mystery box show" characters. The whole bit about the file, where they just say "the file" and then have a long-ass pause before saying "Cold Harbor" was so annoying. This gives 0 explanation to Mark and just works as a wink at the audience like "Wouldn't you like to know what that means?"
Other characters typically speak fairly realistically or at least in a straightforward way that makes sense. Any omissions tend to happen because characters don't ask the right questions. Here, Mark asks the right question and gets fuck-all in return.
The question about drowning might have just been a misdirect for the audience, I suppose? The purpose of the actual Cold Harbor test is clear, though, they present her with a task of dismantling a baby crib, essentially giving up on the dream of motherhood that Outie Gemma had, yet their analytics show she’s feeling no pain about it, meaning their quest to separate a human completely from their trauma has worked. There’s a reason an earlier line mentions freedom from pain.
I’m left uncertain about why they wanted specifically to get ready of her after this test, though. Is that really the biggest pain they could test for? Is there a limit on innie instances? Or is it again some bullshit Kier limitation that’s part of their rituals?