Like pretty much everyone else, I loved the dream sequence. Highlight of the episode. When I saw it I was thinking, "why don't Sakakibara and Mei just troll the class like this?" But then when they talked to Chibiki-sensei the seriousness of the responsibility they have to the rest the class came back. However, Sakakibara's classmates aren't doing as good a job of ignoring him yet. They definitely noticed when he was having his Mei fantasy, with that goofy grin on his face.
Interesting that Mei thought of refusing to be the the one that doesn't exist at first. I still wonder how she was chosen -- drawing lots? Or something else? And twin-tails' method of identifying the dead person is feeling whether their hands are cold? Uhm, okay, god forbid if you have clammy hands, then twin-tails will brand you the dead one.
So Sakakibara was in town a year and a half ago, but he doesn't remember? Wonder what that's about. Also interesting that the success rate of the countermeasures is only 50%. So they're really floundering around without truly understanding the mechanics of the calamity. I wonder what happened in 1983 though (Reiko's year) since it sounds like the calamity stopped? Was that the year the class trip was changed?