Even director George Lucas wasn't safe from McDiarmid's twisted vision.
"One time I yelled 'cut' and Ian turned to me and said 'what if someone just jumped through the middle of the chancellor's office and yelled AAARGRAAGRARGARARGRGGGARGAHGHGHGH? Maybe the Jedi Masters in robes would forget their trained routine of arresting a Sith Lord.' My jaw hit the floor and it never really came back up. That's when I thought, is he getting in character to play Sheev, or is Sheev something that's been in him all along?"
"Sometimes I would go to look into one of the cameras, and I noticed Ian had put something in the lens. It was stuff like 'What if cameras were lightsabers? Are you threatening me, master Jedi?' and 'Lights. Camera. Treason.' I had to ask him to stop because I was getting too scared to direct."