The survivors learn that they are trapped underwater for the Final Killing Game. Kyoko, Ryota, Makoto, and Aoi reunite and share their information.
- All for Nothing:
- Kizakura's sacrifice is deemed worthless, as not many minutes after dying to save Kyouko, she dies by triggering her own NG code.
- Ruruka kills Kizakura, her boyfriend and attempts to kill Mitarai, Kyouko and Sakakura. This is all rendered worthless as the secret exit wasn't even real. To add insult to injury, she dies right after.
- Always with You: Kyouko reassures Makoto she will always be with him, no matter what happens.
- Break the Haughty: All her actions of episode 6 to 8 are rendered pointless and Ruruka loses it, she spends the entirety of her last minutes crying, lamenting Izayoi's death and trying desperately to convince herself she did the right thing and she can make new friends once she gets out.
- Cruel and Unusual Death: Although no death in this episode was not cruel, Ruruka takes the cake with the most violent and gore-y death since Nagito's. She was choked with her own candy, stabbed in the chest, tortured, her body was maimed and bloody when found and god knows what else.
- Characters Dropping Like Flies: In one single episode, the survivor count drops from 9 to 5, with the deaths of Gekkou-bot, Juzo, Ruruka and Kyouko. The lowest count in the main series, considering one of them haven't even appeared and another is implied do die soon.
- Dies Wide Open: Ruruka's corpse eyes are very much open. Also filled with tears and bloodshot.
- Dying Declaration of Love: Izayoi to Ruruka, despite her triggering his forbidden action. Ambiguously, that's also what Sakakura and Kirigiri did.
- Et Tu, Brute?: Subverted by Izayoi's rection to Ruruka's betrayal. He is actually okay with being killed by her as long as she is fine.
- Heroic Sacrifice: Kyoko dies from her forbidden action, due to her refusal to betray Makoto again.
- Izayoi accepted his death as needed to keep Ruruka safe.
- The Paranoiac: The episode solidifies this as Ruruka's Fatal Flaw, she is so unable to trust anyone, she killed her own boyfriend believing that he would one day betray her.
- The Reveal: Kirigiri's NG code is "letting Naegi survive past the fourth sleeping period". The episode also reveals Yukizome and Gozu's, "Letting Munakata die" and "Be pinned down for 3 seconds".
- Recurring Element: Being likely the last victim of the deadly game, Ruruka's death is also the most brutal, similar to what happened to Nagito and Mukuro.
- "Shut Up" Kiss: After Rurka triggers Izayoi's forbidden action, causing him to slowly die from poison, she begins crying over how she couldn't risk him betraying her even though she loves him. He silenced her with a kiss, showing that he forgives her.
- Tempting Fate / Instantly Proven Wrong: Ruruka's last words were promises to survive on her own and make new friends as soon as she left the building.
- Wham Line:Kyoko's NG Code: Makoto Naegi survives the Fourth Phase.
- Wham Shot: Kyoko being found dead due to her NG Code.
- You Are Not Alone: Kyouko makes a small speech of it to Makoto, to remember him they are all in this with him.
