In the 1999 film Cradle Will Rock, writer/director Tim Robbins uses familiar cinematic conventions and popular character actors to build a specific expectation in the minds of the audience. Doing this, he makes the plot itself (which defies most or all such expectations) seem more profound.
Robbins' use of music--always juxtaposing it, as Marc Blitzstein did in his musical The Cradle Will Rock (the creation of which is the story of the Robbins film), with violence--is particularly intriguing. The typical mold of the Hollywood musical, with Julie Andrews singing merrily through the fields, can be contrasted to Robbins' nightmarish vision of Blitzstein's lonely musical number, playing on an imaginary piano while communing with his dead wife who speaks in monotone and surrounded by police officers beating peaceful protestors in a public park.
The blending of music with violence (and other unpleasantness) isn't isolated to the composition scene. While Blitzstein sits in jail, he composes a second song, thinking through plot developments and connecting his plight to that of his characters.
While there is no physical violence in the scene, it's a depressing one, filled with stark, unpleasant noises and a drab background not commonly associated with musical numbers. Further, even when no one is being done bodily harm, a jail is a place of psychological and social violence.
A third musical number (the titular song) is sung by union members who, having been thrown out by their union-busting bosses, charge on the factory to demand their jobs back with a thinly-veiled implication of class war as a consequence if the bosses don't comply. While they are ultimately nonviolent, the union carries shovels, hammers and other implements of their craft that might easily double as weapons.
Where usually the climactic musical number in a film or play is thought to...