Keir Dullea's character is forcing his way back into the Discovery spaceship after the computer HAL has tried to kill him by locking him outside.

"Just what do you think you're doing, Dave?" says HAL with sinister coolness. Dave does not reply, but he's breathing heavily in his spacesuit as he powers towards the room where the core processor is stored. Some rooms he goes through are bathed in blood-red light, others remain lit with a sterile bone-whiteness. Dullea accesses the Logic Memory Centre. "I honestly think you ought to sit down calmly," says HAL, "take a stress pill and think things over."

Dullea accesses the numbered computer core, and each turn of the key releases a part of HAL's memory. As HAL slowly dies, it regresses to an infantile state. It asks Dullea whether he wants to hear the song "Daisy Bell". In a moment of compassion, Dullea agrees.

The choice of this old music hall song, dating from 1892 and written by Harry Dacre, was an in-joke between the author Arthur C. Clarke and director Stanley Kubrick. In 1961 the IBM 7094 computer became the first computer to sing, and the choice of song from the programmers was "Daisy Bell".

Kubrick, ever the perfectionist, went through several choices for the voice of HAL. Originally the British actor Nigel Davenport was hired to feed the lines off-camera, so Dullea could respond to it in real-time. Davenport later went into a studio to record the lines, but by that point Kubrick had decided he didn't want HAL to have a British accent. The lines were now fed either by Kubrick himself or by his assistant, Derek Cracknell. Cracknell, who had a ripe cockney accent to rival a young Michael Caine, is the person singing the song to Dullea during the actual filming.

Kubrick then hired the actor Martin Balsam, best-known for playing the ill-fated insurance salesman in 'Psycho', for post-dubbing. Again, he did a full recording and again Kubrick didn't like it. Eventually, Kubrick settled on the Canadian actor Douglas Rain. Kubrick was pleased with the "patronising, asexual quality he elicited from the actor", according to Vincent LoBrutto in his biography of the director.