Does Scorpions tell nonsense in episode 4 (Netflix)?

As a result, an iron button is wrapped in a viscose cloth together with some chlorine (rubbed from a toilet stone) and rubbed with the outside on a metal grid.

Toxic chlorine gases then escaped from the cloth. The whole thing, including the cloth, was stuffed into a beard lock, where he then twisted the lock bars inside and let the door open.

What is physically / chemically possible and correct?

So that chlorine occurs in toilet stones is hardly possible - chlorine is a gas…

it is more likely to be chlorine compounds (chlorates? Or something?) - you should look there first.