Ooh, OK. Thanks for taking the time to explain! I did get the sense of the letter being an addition, and wondered from whom; the fact it's not revealed conveys how easily doctrine could be changed. And with Ruth being unchanged, that questions the authority behind the 'we shall ALL be changed', but also more broadly the question of why some are changed and some are not is left to Ruth/Caleb to wonder, to try to make sense of based on their decisions instead of on scripture/preachers - a kind of broader commentary on a divide between God and his interpreters(?)
(Thanks for adding more on the game's page. It's a really interesting read!)