They are only available in extras mode once you beat the boss. They don't triggered when you are defeated by bosses.
Hello,
I did not had much idea about game design and programming back then. Now after having interactions with people I am taking notes of what kind of feature I should implement into game. The common one being accessing images during playthrough. Even if that's additional work but it will be a lot easier if I planned it earlier.
I'm glad you like her playthrough. Originally I was going to add extra three level for Ken's story but added her gameplay which I think is preferred by many players.