Prior to this episode, the whole cast has been shown as normal highschool kids in the "back classes". But Nagisa starts of the day showing his potential in the art of assassination.

As the episode goes on, it's clear to Nagisa's PE Instructor, Karasuma, that Nagisa has the most killer potential out of everyone in the class (Aside from Koro-sensei, ofc).

This episode also sets the stage for the grand season finale of Nagisa vs Takaoka sensei in their final round. One of the most hype moments of anime in 2015.