In this sequence of "The Third Man" (1949), the location, lighting, and other factors contribute to a very effective chase scene. The location of the sewers and the fact that Harry Lime uses them to travel around Vienna relates to his character and the type of crime he has committed (selling watered-down penicillin to hospitals - this is not strong enough and leads to the deaths of many children. This is a dirty, horrible crime - like the dirty, disgusting sewers. He is like a plague rat running through the sewers - he is spreading death and illness to people as he travels. He is also like a wasted human - like the waste in the sewers. The fact that he is running around and hiding in the labyrinthine sewers also makes him like a test or lab rat, trying to escape the maze. Furthermore, as he has plunged into crime, his descent to the sewers reflects that. There is intertextuality here, as this is also done to the extreme in "Kill Bill Volume 2", when the Bride is buried alive. This puts her into a dark, enclosed environment - like the sewers of Vienna.
The lighting in this chase sequence creates brilliant effects - it is a great example of chiaroscuro lighting.
For example, in this shot the chiaroscuro lighting is used as a lighting tool, and for effect. The spotlights are like searchlights, which also refers to the searchlights of the recent Second World War which has greatly damaged Vienna. The lighting also reflects off the wet brick surfaces, to create a very effective shot that completely exposes the criminal, Harry Lime. There is also a vanishing point, where the seekers of Lime are. This makes the vanishing point the end for Harry Lie - his capture awaits there.
In this shot the floodlight is lighting the sewer. The wide area with the floodlight gives a sense of no escape - you cannot hide in this area.Furthermore, the lighting reflects off the water on the walls, floor and cieling to create a mirror effect, which creates illusion and an ominous, creepy look. In addition, this shot contains a clear vanishing point at the source of the light. As Harry Lime is running into the light and the vanishing point, it creates the sense of him running away "into the light". This is a well-known phrase for dying, so this is foresahdowing the end of the scene where Harry Lime does indeed die. Many vanishing points are used in this film for effects such as this e.g. directly after this scene when the enigmatic figure Anna walks past Holly from a clear vanishing point.