several months grooming and experimenting on him. Though Robin's abilities have grown to unprecedented levels, he gradually becomes increasingly unstable from the psychological strain of his superiors' machinations, culminating in a mass murder inside Old Chicago, an indoor amusement park. As Peter and Gillian infiltrate the mansion, Robin senses her presence. Believing that PSI intends to kill him and replace him with another psychic, he finally snaps, telekinetically torturing and killing Susan. Peter confronts his son, but Robin, a now-schizoid, furiously attacks him. Robin is thrown out of the window and scratches Peter when he tries to save him from falling. When Robin plunges to the ground, a distraught Peter flings himself after his son, thus killing himself. Robin lingers a bit before finally dying, and seems to make some form of psychic contact with Gillian; he transfers his refined powers to her, implying that she will save herself from Childress and avenge his death. The next morning, Childress approaches Gillian and starts manipulating her to get her to connect with him. Understanding his long-term intentions, she embraces her psychic abilities and avenges the deaths of Robin and Peter by causing Childress's body to explode. Cast Actress Hilary Thompson (Cheryl) had her dialogue redubbed by an uncredited Betty Buckley. Production Parts of this film used the grounds at Old Chicago of Bolingbrook, Illinois, a now-defunct amusement park. The scene at the hotel when Kirk Douglas escapes the agents took place in a room at the now-defunct Plymouth Hotel, the same room and hotel used in the 1980 film The Blues Brothers. Other filming locations included the Water Tower Place, Lincoln Park, and Navy Pier. The PSI headquarters was a Georgian-style mansion in Lake Forest. The opening sequence was shot in Caesarea, Israel. The interiors were filmed at Stage 5 of 20th Century Fox studios in Century City. In an interview with The Talks, De Palma said that he had 8 or 9 high-speed cameras to film Cassavetes exploding in the film's conclusion: "The first time we did it, it didn't work. The body parts didn't go towards the right cameras and this whole set was covered with blood. And it took us almost a week to get back to do take two". Originally, the "psychic powers" effect was depicted through golden-yellow "glowing eye" effect. During post-production, the effect's color was changed from yellow to blue. The original effect can still