
Did they just indirectly revealed a major thing about URM in the artbook of Fire and Ash?
Also if you read Alita official artbook, you know that Cameron at some point thought he would do Avatars for the rest of his life, so all the themes he wants to explore, he needs to explore within Avatar sequels.
So I see possibility that some themes he initially wanted to explore in Alita trilogy, he pushed to Avatar because he had imagined he would never make Alita movies.
If that's true, this could be one of them.
(Maybe not a soldier yet, but training 10-years-olds for a specific military mission counts I guess)