She should be fired for belittling the student and telling her to leave the class.
She should also be fired for writing a fake apology.
Of course, at the second firing she’ll be able to say, “You can’t fire me... I’m fired!”
A boss once told me that "there are certain things that, when you've said them, there's nothing left to say." This would appear to be one of them. No way that woman will ever treat that kid fairly after this. Adios, homegirl. You broke it.