Trivia: Often times when a movie is distributed the name of the movie on the actual can is changed or altered to prevent piracy. The name on this movie was "Hal," a reference to "2001: A Space Odyssey" (1968).
Trivia: The very futuristic single bladed fan we see in Spooner's apartment is actually a ceiling fan of today. It's called "The Enigma" and is manufactured by Fanimation Inc.
Trivia: Alan Tudyk, who did the voice of Sonny, is actually visible in the film for one frame. When the stand-in robot is killed in Sonny's place, Alan can be seen in the brief flash after the nanites are injected. Confirmed on Visual Effects Team commentary. (01:18:20)
Answer: Sonny killed Lanning. Lanning had designed Sonny with the ability to opt out of the Three Laws when he deemed it absolutely necessary. Lanning forced Sonny to promise to do Lanning a favor, then told him the favor was to throw Lanning out the window. Forced to keep his word by Lanning's own programming, Sonny overrode the Three Laws and tossed Lanning out the window.
Phoenix