I had to share this comment from a friend who is an accomplished pianist and composer herself  : "She certainly is very talented! But, in this exercise, in her improvisation, she switched the first note from B natural to B flat which nicely put the piece in a comfortable key of 2 flats. She chose the relative minor key to Bb which is G minor to create her piece, making it quite simple to form a piece in the Classical era style. If she utilized that B natural which was chosen from the hat in her improvisation, this would have lent itself to a greater challenge as she would have been dealing with two tonalities and the ear wouldn't have accepted it as well. Still, she did a nice job, but, unfortunately she took the easy route and altered that first note."