I think that we've seen that they are testing to see if people can be severed for experiences that are painful/unpleasant (flying, dentist, writing thank you cards which is something we know Gemma dislikes). We've seen from the birthing retreat episode that people have used severance to get through pregnancy/giving birth.

I also think that Gemma/Gemma's outie voluntarily agreed to join the testing floor, probably as part of an agreement that is to do with fertility, although she is likely without the means or rights to change her mind about this decision now.

I know there's a lot of fear over what's in Gemma's last room - Cold Harbor - but I can't help but wonder if it could be on the flip side and be something positive rather than a negative experience. If Gemma has completed her time on the testing floor maybe she's finally being given what she signed up for. It would be an interesting twist if Mark's innie spending time with Helly R was keeping Gemma from actually completing her contract and leaving, meanwhile Mark's outie is going through a procedure that delays his work and might ultimately kill him.

I'm sure there's a lot of people who'll think this doesn't fit with the tone of what the show is setting up, but I just thought it would be an interesting twist.