2 points to raise
Eren has been having flashbacks often because he was really calm during the experience. He wasn't shocked or confused ("What is this?", "Who are you") but rather accepted and made conclusions ("this is a flashback", "Historia?"). He even knew how to act ("if I kept thinking...
One of the things that make DGM so interesting is how Hoshino uses shades to hint at the unwritten and the speculative. Commonly, it's just protagonist white and antagonist black but she goes a step further and uses it to spark doubt, conflict, and analysis of character and themes. There's a ton...
