The real reason that she never takes off her helmet? Phasma is actually a tentacle monster posing as a humanoid.

You discover this by accident. Obviously, Hux knows all about it already. So when you try to tell him, he betrays you to her slimy embrace.

Your re-education does not follow the normal procedure.

+ Femslash preferred but e.g. Hux being a secret slave to the tentacle goddess would also be fine.