 Director Friedkin, William (qv) went to some extraordinary lengths  to abuse the cast. He fired off guns behind the actors to get the  required startled effect. When Fr. Dyer is attempting to administer  last rites to Fr. Karris Friedkin was not satisfied after several  takes. He took Fr. Omalley aside and asked "do you trust me?" Fr.  OMalley said yes just in time to get slapped across the face.  Freidkin immediately said,"action" and the result is authentic. He  even went as far as to put Blair, Linda (qv) and  Burstyn, Ellen (qv) in harnesses and have crew members yank them  violently.