as an attendant or psychiatric aide or whatever the current PC term is....I assisted Old Doc Tilly in his semi regular task of giving electric shock therapy (more correctly called, but not used by us grunts at the time...Electroconvulsive therapy)....Doc Tilly did not use the timer feature on the instrument....he would hold the button until he felt the patient got a goodly jolt before releasing it and then the patient would go into the convulsions ala Randle Patrick McMurphy...
btw Jack Nicohlson must have studied videos of electric shock therapy because his performance was spot on....