Also if the operator can't see an alteration in the graphs, he can think that the subject has been "inmune" to the machine and try to break him "manually" like

Also if the operator can't see an alteration in the graphs, he can think that the subject has been "inmune" to the machine and try to break him "manually" like in the linked article or like arockwell's wife. The drugs would be used because, as the interviewer himself said in the linked article: "everybody have done drugs some time", so it's a good guess, even if it's "most people" instead of "everybody".