On the off chance someone reading this hasn't seen it, Arai-san is referring to the events of episode 12.1 in this talk.

Also, re: Arai's third bubble in the fourth panel: 大冒険活劇 seems to be a set term in Japanese, but I couldn't find an established translation for it, hence the awkwardly literal "action drama of ... great adventure."

I also feel the bubble would best be translated like one of those long Victorian novel titles, but I couldn't think of anything I liked.

FriendOfTheDevil said:

Also, re: Arai's third bubble in the fourth panel: 大冒険活劇 seems to be a set term in Japanese, but I couldn't find an established translation for it, hence the awkwardly literal "action drama of ... great adventure."

Action-adventure story (or action/adventure...) is the corresponding set term. Occassionally you can shorten it to "adventure story" (because action is usually implicit) or tack on epic/grand at the beginning (or use epic like a noun, i.e. action-adventure epic) if you want to emphasize the 'greatness' aspect of it (like if the story actually qualifies for the epic genre).

The Japanese will tack on 大 to 冒険 (in titles) whenever they can get away with it, because 冒険 has some other meanings (literally "to venture a risk") that can have a slight negative connotation. Putting 大 emphasizes the romantic aspect of it. Since 大 occurs so ubiqutously as part of the set phrase, it is sometimes dropped in translation (hence just 'action-adventure story'), especially if the resulting translated title is already excessively long and adding another intensifier would just make it sound gauche.

FriendOfTheDevil said:

I also feel the bubble would best be translated like one of those long Victorian novel titles, but I couldn't think of anything I liked.

The action-filled epic, "The Adventures of Ms. Coon (esq.) and Fennec in the Search for the Platonic Sphere!"