It is revealed that Amethyst stayed in the ground 500 years too long, resulting in her being an "overcooked" and smaller version of what should have been a standard Quartz soldier like Jasper.

She identifies the injectors at the Kindergarten as "Era 1" models.

This is a pivotal moment for Peridot’s "redemption arc." She experiences guilt for the first time—a feeling she describes as feeling "small"—and makes her first genuine effort to apologize and understand others' feelings. Cultural References & Trivia

Peridot recording her thoughts on a tape recorder is a direct homage to Special Agent Dale Cooper from the show Twin Peaks .