Here's why:
* The Hive Queen is a boss in the Earth Kingdom level "The Day of Black Sun." The goal is to defeat her by pushing her into the lava pit.
* Defeating her doesn't actually kill her. She survives the fall and eventually returns, as seen in the Avatar: The Last Airbender animated series.
* The game focuses on defeating her as a threat to the Earth Kingdom, not on permanent eradication. This aligns with the story's themes of balancing forces and avoiding unnecessary violence.
Therefore, you only defeat the Hive Queen in the game by pushing her into the lava, not by actually killing her.