Episode 7 is my favorite episode, and Ekko is my favorite character. Schnee did a really amazing video about him, which really helped to crystallize what it was I loved about the character. Piltover and Zaun are both corrupt in their own ways, but The Firelights are the ones focused on building and protecting.
Two things about that final fight, though. One, the firelight bombs seemed to have sought out weapons, so by trading her gun for Vi's medicine, Caitlyn might have saved herself... at least accidentally. Second, in the lore, Ekko's magic is about time manipulation, and being able to repeatedly rewind fights that go badly for him (you should watch the Ekko Seconds video). I like the idea that the scene where you are seeing them as kids is actually Ekko replaying that fight over and over again until he comes to an outcome where they both survive.