Well, the episode was about (un)necessary sacrifices. Blake and Sun mentionning how reluctant the people of Menagerie were to fight, Ruby about how Pyrrha and Penny's deaths meant she can't not fight Salem, and Ilia and the brothers talking about Sienna's and soon the Belladonna's. Black Sun is pretty much sunk, and I doubt they wanted to have a romantic relationship between Ilia and the Albains (or between the last two).
Anyway, I just don't see it. Sure, Oscar is looking up to Ruby, but it might just be genuine admiration. Maybe kindcof a big sister, little brother kind of deal. If it's a crush, it's one-sided. She's nice with him, but that's because Ruby is a kind girl. Especially in V6 when the few times she interact with him:
-She tries to reassure him abput being his own person, and her lack of denial may imply she was lying to make him feel good (though I doubt it, she's a bad liar).>Being just as much worried for him than Weiss.
-commenting on his clothes.
-Being vexed he asked if she's okay while he and Maria were under fire when she told them to stay low because they need that ship.
-Trying to deflect the praises away from her and settling on him, while calling him a "fourteen-year-old farmhand".
If people see that as Ruby being interested, then she must be secretly banging Jaune, with whom her interactions this volume were much more meaningful even though they're not necessarily intended as romantic.