In my opinion, the reason why Levi decided to save Armin instead of Erwin is that the night before the mission to reconquer Wall Maria he secretly listened to Eren, Armin and Mikasa talking about their childhood dreams. Probably he remembered of his friends Isabel and Farlan. He saw himself and his friends in Eren, Mikasa and Armin. And they were able to realize their dream and see the ocean together thank to Levi.
[I love thinking about how history will describe Rom after the end of DS9: “Grand Nagus Rom was responsible for major reforms in Ferengi society, and was also a technological genius who made several contributions to the Alliance efforts in the Dominion War. His mother, Ishka, was a pioneering feminist activist, and his wife Leeta also contributed to Rom’s successes. His son, Nog, was the first Ferengi to join Starfleet. He also had a brother who owned a bar on an old space station.”]
and Armin are a very strong literary parallel to Adam and Eve, a set of characters in a heavily studied famous Bible story and a massively utilized symbol in several pieces of literature. The
implications in that are very intriguing but this is just a discussion
of the parallel, not a set of predictions or ship discourse on the matter.