The whole variety show marching band thing was pretty wtf, but all of you acting like you'd run out a door that will end your existence are full of shit. Even re-integration would sketchy as hell. Wouldn't it just be outtie Mark getting innie Mark's memories and innie Mark not existing anymore? They had a whole conversation about that and innie Mark never signed off on it, he didn't even back out of anything. People will just out of high story windows when the building's on fire, doing whatever you can to buy a few more seconds of life isn't abnormal
Also not seeing where people are getting the "Lost" vibe from. Those shows throw random crazy shit at you constantly, while this just slow drips the answers and nothing's been too off the wall. There's still time for this to go full retard, but shows like 12 Monkeys and Mr Robot were far crazier at the same point and both ended up amazing.
Transferring people's minds into others bodies seems to be the obvious place they're going, with bringing Kier's consciousness back as a form of resurrection the most likely end goal.