Hajimete no Otomodachi wa Zombie deshita - Vol. 2 Ch. 11 - Episode 11

[faaresemo]

and they were both yanderes!

Okay, page 21 confirms to me that we got a big ol' case of the unreliable narrator going on here.

you didn't catch wind of that back when Eko left the security room to find Risa and in the 5 minutes that would have taken, everyone else had woken up in the middle of the night and had a battle royale?