@Ryrie
it's easy to only see positives when stakes are low and there is no conflict to test the characters. Akira is in a unique position of seeing the whole playing field now. She is the only one who knows that Mayuki likes her, Rin likes Mayuki and she likes Rin. The other 2 only know their own feelings (and maybe Rin knows that Mayuki likes Akira, but she is also the most likely to accept that situation if she is not left behind).
And she still decided to put her trust in Mayuki, even when she knows that the most likely outcome of it is someone/everyone getting hurt. On top of that, she is probably in the worst position out of all of them, because Mayuki and Rin have a fairly obvious line to become romantic partners, but we haven't seen anything suggesting Rin sees Akira in a romantic way.
She also almost immediately recognizes, when presented with evidence, that Mayuki is not just a child with nothing going for her, even if it would be easy to just keep hating her rival, but that she is legitimately superior in some ways. And, again, ends up putting her trust in Mayuki shortly after.
Absolutely amazing character.