Unfortunately, it's not that much of a story. When I got into the arena, I remembered something. Someone told me that people were going to die horribly, but that they'd make an opening for me to kill them cleanly. I couldn't remember who at the time, but it happened just like they said.
Then in the game, someone told me when to strike. I...think it might have been Flowers. She brought their bracers down, and defeated Trickster's defenses.