Arthur and Ollie failed at Blackgate. The break out proceeded unheeded, and when Dinah tries their signal devices, she gets nothing. Their ear buds must have fallen out. She double checks her before going after Batman.
She finds him. as expected, in Gotham, where he's been distracted himself from the Music Meister in dealing with the hypnotized Blackgate escapees.
On her way to find Kamala, Dinah watches him from a nearby flat roof, debating whether or not he'd need her help.
He doesn't. He never does. Even with that ridiculous costume, the armor and the impractical cape, he fights like Ted. like a real fighter, despite all the show, it's never gimmickry. One man, surrounding by crowds of hardened criminals, his flawless technique and armor helped by the fact that they''re not fighting under their own control.
She finds herself pausing just to watch the dance of his movements, perfectly in time with the music in her head.
She doesn't even notice when she starts singing. When she realises, she notices that she's still in control. She's still able to fight, and she's still herself. Until the Music Meister shows up, and joins in her song.
With a love song.
Thankful for her earplugs, Dinah's main concern isn't just the disgust of a villain desire for her, but a reaction to the huge gun in his hands. She spins towards him and screams to get it out of his hands.
It's the music! Despite the protective plugs, she can't control her voice enough to get a Canary Cry out! Dinah calls, but all she can manage is within the key of the song. In frustration, she lunges, only to be hit by an energy beam that sends shockwaves of pain through her torso.
The last thing she sees as she falls, is the fallen gauntlet of the Bat. She left him alone and he'd been defeated.