We don’t have much information to work with. The unanimous vote, twice in a row, indicates the presence of a cluster (x traitors).
If no innocent player voted in these two rounds, then we have x = 6 traitors (out of 13 players). The use of phones also allows for coordination in subsequent rounds, so it’s possible for only the traitors to vote without losing their anonymity.
Clearly, Akiyama and Yokoya are working together to expose the traitors. It wouldn’t be too far-fetched to assume that they wrote the initial note themselves so they could start the Snitching Game (after all, it’s Yokoya’s place). The fact that they allowed cell phones seems to be a calculated move.
I wouldn’t be surprised if the hologram was their creation (after all, Yokoya could certainly pull that off).
Did everyone really feel like they were being watched in Chapter 1, or was it a herd effect (as explained in Chapter 2)? Were the camera and microphone in Chapter 1 Yokoya’s creation?
I honestly hope this final Liar Game doesn’t end too quickly.