This involves an old and dangerous route, used as an example only, not because it is the safest or ‘best’. Reaction releases deadly hydrogen cyanide that can only be contained with an appropriate fume hood or trap.
These derivatives are fully legal in many countries, but always check local regulations. The product in this video is legal in my jurisdiction. For educational and documentation purposes only, not a tutorial.
Don't conduct any chemical reactions without proper and professional safety analysis and risk management. Measures taken can be invisible, not filmed, not properly visible on camera or misjudged by the viewer due to setup or video construction. Always conduct own appropriate measures regardless of video setup.