I have to give props to Hickman for digging into X-lore and putting all of this together. He knew Synch was a fan favorite and people were clamoring to see him again (even before we knew of the protocols), molding the Vault concept to fit their powers and then creating this sense of urgency and danger. It's absolutely fantastic. And it addresses some of the talk about deaths being meaningless - well in this case we don't even know if they're dead or not or lost forever.