Everyone messes up with their pronouns in compelled speech because their mind and brain are screaming at them that they are uttering untruths. Their lips are trying desperately to say the truth while their brains are telling them to comply.
"You are a slow learner, Winston."
"How can I help it? How can I help but see what is in front of my eyes? Two and two are four."
"Sometimes, Winston. Sometimes they are five. Sometimes they are three. Sometimes they are all of them at once. You must try harder. It is not easy to become sane.”
“In the end the Party would announce that two and two made five, and you would have to believe it. It was inevitable that they should make that claim sooner or later: the logic of their position demanded it. Not merely the validity of experience, but the very existence of external reality, was tacitly denied by their philosophy. The heresy of heresies was common sense." (George Orwell 1984)