As the show progressed it became clearer and clearer how innies and outies are the same person just with different memory and experience. They use the same language (Dylan's love for "fuck you"), have the same orientation (all characters), same leading character traits (Mark being an asshole but showing bravery enough to do dangerous things for his loved ones (oMark burning his eyes and drilling a hole in his skull, iMark breaking all the rules he used to follow for years, taking Drummond as a hostage) or Helena looking for human connection, having a strong character (Helly tried to kill Helena, yet Helena returned to the floor, recording an explanatory cover-up speech the same night as the party happened; Helly recuperating rather quickly after discovering she is an Eagen, waking up after being drown in a lake)), Gemma endured psychological torture both as an outie and as an innie, didn't break.
In Multiple personality disorder a person's body is a vessel for several personalities that can be very different. If a part of a brain is damaged (physically destroyed), a person's character can also change dramatically. However, with the Severance procedure the chip blocks access to the memory and feelings associated with an event, the character traits stay the same, the brain network isn't changed much. Mark feels strongly for a woman, his feelings are just attached to a different face when he is iMark, the memory and understanding how the lover should look was erased, but not the longing.
There was a case of brain damage when a man stopped recognising his family members visually, but still responded to their voices. A husband would recognise his wife on the phone, but treat her photo or in real life as a stranger he doesn't know.
iMark is oMark with a memory loss, it's not a new human, not a conjoint twin. However, of course, as a human with survival and self-preservation instincts, he will fight for his life, think of reintegration as dying, however bleak or constricted life on the Severed floor is.
Interestingly, we were already shown how an innie gave up on his life (was suicidal, then made a sacrifice to protect friends), and in return actually got what he wanted, what he lost (Irving meeting with Burt).
With this new interest Jame showed iHelena, and the sad life Helena leads, it looks like Helly may be the one version to stay in the end (or choose the reintegration, at least).
















