Poor page-four Icchi. I was briefly afraid for his life.
The manga made this situation much more clear to me. It's more obvious here that Yamada understood that Ichikawa's words can be applied to them (Yamada and Ichikawa) as well, while Ichikawa didn't understand the implication.
But I personally couldn't "read" it in Yamada's expression in the anime (season 2, episode 7):
Plus, when Ichikawa asks why Yamada made the face, Yamada changes the topic very quickly in anime, while in manga, it totally depends on how fast you're reading, so you've got a bit more time to think about this panel.