Amygdalin is hydrolysed by two enzymes (amygdalin hydrolase and prunasin hydrolase) most correctly in crushed, moistened kernels, resulting in the formation of HCN and glucose Hydrolysis (the interaction with water) causes the damp solid to release trace quantities of hydrogen cyanide. A normal description in the scent of hydrogen cyanide https://cyanolab.net/potassium-cyanide/