Rose Cut Jack’s Hand Off
You’d have to be crazy to let someone use an axe to free you from handcuffs, especially if that person closes their eyes before taking the shot. And if you watch Rose swing the axe closely, you’ll see she wasn’t supposed to make that shot. She actually hits Jack where his wrist is, which would effectively remove his hand if it were real life and not movie magic.
That would free him from his handcuffs too, but in an arguably much more painful way.