Shinji stares fixedly at something. Touji peers at him reproachfully.
Toji:“Hey, boss”
Shinji:“!?”
Reichu: Toji's actually saying “sensei” (or, rather, his clipped Kansai version, sense). Now, I'm not quite sure what this implies when used among buddies, but here it's been translated as both “big shot” and “chief”.
Azathoth: Not that I know a damn thing about Kansai-ben, but I always interpreted it as a comment on Shinji's stuffiness, formality - his general sense of not being "one of the guys".