To someone who knew, or at least seen Myne and later saw Rozemyne, it would make sense that a noble might mistake one for the other. After all they "look really similar." ^^
I bet this will spawn some memes, with bunnies saying "Come with me, if you want to live" and the like, or someone overlaying a shumil over the Monty Python killer bunny scene. ^^
I hope that if the anime doesn't end before this point, WIT will not censor this scene too much.