To show Penelope the wonders of his invention he decided to show how it works on them. He put the handcuffs on their wrists even before Penelope can stop or protest about it. Still, she examined the handcuff on their wrists and sees its quality. Yuriel added that no one can also destroy the handcuff because he focused on its sturdiness too.
But when it was time for them to remove it, Yuriel cannot unlock the handcuff anymore. It is because the key is not with him. The young wizard just remembered that he left the key for the handcuff around their wrists in the Levitating Tower. Yuriel also tells Penelope that he cannot use his magic because of the magic deflector he put on it.
