Episode 4 was all about revenge. Revenge of the white censor fog! Revenge of the unit vs the main character. Heck for a bit I thought we was gonna see something rare. But it went half way. We learn the main character is out for revenge. The engineer wants revenge for her " new" job. Yes revenge is in the air!
While it did not add a lot of new things to the gene, it did do things well in this episode. An yes the hq guy from the mechs company must be akin to the devil with glasses from Log Horizon. He stole the episode.