The key postulate of the Cody’s Lab video tutorials is - do not try to repeat it at home, even step by step following the instructions. As a professional chemist, Cody knows the difference between general toxicity and dosage. He demonstrated this by dissolving a deliberately lethal dose of cyanide in a liter of water and drinking from a glass without any consequences for himself.
Cyanide is a key component of the Cyclone B chemical warfare agent, with which thousands of people were executed in Nazi camps. It has firmly entered the culture as a reliable and quick means of murder, the favorite weapon of spies. The only nuance is that cyanide appears everywhere in the form of a concentrate, small tablets of dry matter. But if you dissolve it in water, its properties change dramatically.
Cody clearly showed that cyanide is not evil in its purest form, it is just a chemical that can be handled in different ways. And not only to drink on camera, but also to make beautiful compositions like "Prussian blue" using simple ingredients. Alas, this requires knowledge in chemistry and a little experience - do not try to surprise guests with unusual tricks.