Dont buy an iron dagger, crit doesnt seem to be implemented.
There's only 2 scenes from what I found, one from losing to her and the second one if you bring her down to like 30% she'll follow up with an attack. It seems impossible to beat her though, level capped at 5 and she will use pots and steal your own pots when you try to heal yourself, so no matter what you do seems like you'll always lose so I couldn't find any other scenes.
If anyone else found extra scenes please let us know and many thanks for the upload.