I jokingly asked her, "How exactly do you hold a knife when you kill people?"
Without flinching or hesitating, she turned the knife over (icepick grip) and said, "I sneak up behind, grab face like this and jerk back. Then I stab in neck two or three times!" (pumping her hand up and down.)
Important for folks to realize that generalizations may often turn out false when applied to people who may have actually done what you are teaching, and not in the dojo.