Good - Himari needs a push on this. Some people can handle ambiguous relationships well, but Yori is clearly not that person. She's building the performance up in her mind as this silver bullet to make Himari love her, but what if Himari just enjoys the music, and doesn't magically fall in love? The current vague situation would continue, with all the jealousy and frustrations that Yori's been experiencing. An extended period of ambiguity could even lead to Yori resenting Himari, and ruin their friendship as well as their romance. Hopefully Aki coming out as Himari's rival will force Himari to realize the current situation is unsustainable, and that she needs to make a decision quickly - even if its a no.