Azula hears her brother's screams and revels in it. She watches and watches, because her eyes are hungry and she can't seem to get enough of the flame, his writhing, his broken sobs. She loves it, because now, all eyes are on her. It's been confirmed. She means more to her father and country, more than her brother ever did. It's only fair. After all, she is the strong one.
She wonders why her brother put himself here in the first place. It was a good plan, a smart plan, something she would have done herself. So what if a few soldiers died? Many had before, what did a few more mean?
She vaguely remembers overhearing a guard ask why she was learning to firebend, many years ago. After all, her brother is the heir. Her brother is stronger.
Lies, she thinks. Her brother is weak; she has not so easily forgotten his pleas, his tears. He will thank Father one day, for making him stronger, and her, for being the one to see his many limitations first.
She will show them who is strongest, one day, one perfect day, when she burns Ba Sing Se to ashes and smiles a bitter sweet smile, like she does now.
But, at the moment, she'll just enjoy this small victory.