Having left the students in detention, Miss Quill joins headteacher Dorothea Ames, who promised to help her remove the creature known as the "Arn" forcing her to obey Charlie's authority.

[1] Vodzilla praised the performances of Kelly, Quesnel and Okonkwo, and the "imaginative world-building and character development", and calling it "the most vivid and ambitious episode of Class to date".

[2] Cult Box gave a positive review, praising Kelly's performance, Quill's character, and the visuals, stating that "the succession of contrasting locales were a treat".

[4] Den of Geek gave a very positive review, praising Quill's character development, Kelly's performance, the writing and themes, and special effects.

Stating that "the concurrent-episodes structure worked a treat", they felt that "what started out looking like a fun, straight-up adventure game [...] quickly pivoted into an intense exploration of character and the philosophy of liberty.

They felt that "there’s a real depth of textuality to ‘The Metaphysical Engine’, which demonstrates a lot of Patrick Ness’ greatest strengths as a writer" and that the writing was "both entertaining and thought provoking".

[6] Mym Buzz gave a positive review, calling the episode "a gloriously entertaining mess" and "a fine, pacy, unpredictable, great-looking and unashamedly geeky piece of small screen sci-fi".