In "The Last Jedi: Expanded Edition" by Jason Fry, Kylo Ren reflects on a critical moment after a confrontation with Rey. The general informs him that Snoke's escape shuttle is missing, prompting Kylo to weigh the implications of Rey's actions during their encounter. He realizes that Rey had the opportunity to defeat him but chose to spare his life instead.
This decision by Rey leads Kylo to contemplate the nature of their connection. He senses a possible underlying bond between them, suggesting that Rey may still harbor some feelings of care towards him despite their conflict. This idea challenges his understanding of their rivalry and hints at deeper emotional currents at play.