Insecurity, fear of judgment, lack of confidence, shame, need for privacy, I can think of a few. It doesn't look like a game played against Fallon, rather, it could be a camouflaged denial.
Some are too proud, too stubborn, sometimes simply not ready to allow to be helped, or admit that they don't want to confront the truth. So they hide behind questionable reactions.
There's no winning with that tactic either way. Fallon might have crossed a limit, and she had to waltz away. It's a draw.
I can't be sure that this is an appropriate answer to the situation, but it might help Fallon to find it herself.
Happy birthday
May your orange box become what you want it to be, perhaps filled with questions for another video, perhaps more than that. I, sadly, have none for you at the moment, but I will think on it!