Ok....I don't remember this episode in the manga so my best guess is it's an original anime episode. It's a pre-Christmas episode that doesn't correspond to any chapters of the manga. There's the introduction(?) er🤔 appearance would be an appropriate word of Miller's other colleagues and of course they are even more eccentric than Fomalhaut. The episode probes into Mimori's true feelings toward Miller, and the next episode is sure to be highly anticipated.