As he protests, Quill reminds him that although he forced her into slavery and refuses to avenge the genocides of their species using the Cabinet of Souls, she as a teacher has the authority to put him in detention.

As Charlie starts getting panicked due to his claustrophobia, April, who has another key, opens the door for him; as she does, a meteor flies through a nearby tear in space and time right into the detention room, causing a small explosion.

This leads Tanya to the conclusion that the stone is of alien origin, forces whoever holds it to tell the truth, and is also making them progressively angrier.

Forced to act faster as Charlie starts having panic attacks due to his claustrophobia, April grabs the meteor, who has gotten more powerful: she is able to reveal that they were taken out of space and time, meaning they will not age or die, but will stay trapped here forever.

As Charlie had confessed every secret he had and proved he was more guilty in his heart that the prisoner himself, the stone breaks and the classroom and students are teleported back into their normal place in space and time.

As the other students leave the classroom deeply angry at each other after all those revelations, Charlie, asks a transformed Quill, now with a scar on her left eye and inexplicably longer hair than 45 minutes ago, how she is now able to use a gun.

She reveals that the creature he put in her mind to enslave her and stop her from running wild has been removed, and that she now has her freedom of action back; she states that things are going to change.

The conflicts between the characters and reveals of their true feelings were praised, together with the episode's writing, directing, and performances, notably Greg Austin and Jordan Renzo as Charlie and Matteusz respectively.

He also stated "The central conceit of the episode is able to transcend its apparent artifice, instead providing the impetus for some powerful character drama.

He also praised the "clever scripting" and "very stylish direction" for making the episode visually appealing, and the performances (Greg Austin's in particular), and stated "There’s great acting throughout and some marvellously awkward moments as the 'truths' are revealed.

And that feeling of 'not connecting' is a theme that’ll ring true to anyone who’s even been a teenager that’s ripped right open and left raw and bleeding here.

"[2] Vodzilla gave the episode a 9 out of 10, highly praising its inventivity and performances, and stating "'Detained' is Class at its best, plunging the group into a situation where the intensity of their relationships with one another works hand-in-hand with the relatively short time they’ve known each other to wreak emotional havoc.

Cult Box gave the episode a perfect rating of five, stating "Director Wayne Yip (Utopia, Misfits) effectively sold their confinement, the escalating levels of mistrust and the sense that they were not alone with some terrific close-up camera work, and a filtered pov during the moments of possession".

[7] Fortress of Solitude highly praised the cast, stating that "the performers handles their role superbly, with each of them having a moment to shine", and the conflicts between the characters.

[8] Several critics favourably compared "Detained" to the Doctor Who episode "Midnight", which also featured a group of characters trapped in a single room.