Fantastic Beasts and Where To Find Them
After Gellert Grindelwald (disguised as Percival Graves) sentenced Newt Scamander and Tina Goldstein to death, Bernadette helped lead them to the Death Cell. She extracted Tina Goldstein's memory and cast them into the Death Potion and encouraged to get into the pool which would've killed her if she got in. Just as her fellow executioner was about to do the same with Newt Scamander he broke free using his Bowtruckle to pick the lock on his handcuffs. Then he released the Swooping Evil which knocked out the third executioner. The second executioner tried to use her wand on Newt Scamander but he redirected her aim hitting Bernadette with a Stunning Spell.