Imagine: you’ve gone up to the very top of the Empire State Building in New York City, to an observatory at the very top that's encased in glass. As you’re observing the ant-sized people on the city streets below you also hear a bomber-style plane getting louder - cool, you initially think, it must be a demonstration. And then - you realise with a sinking feeling - it’s coming straight at the Empire State. And indeed it crashes into the 79th floor, not that far below you. There’s an explosion, you see occasional flickers of flame, and then things start getting uncomfortably hot. The elevator shaft has been damaged, and you’re basically stuck at the observatory, unsure if the Empire State Building is going to collapse, if you’re going to plummet to a fiery death.
And while all of this is happening, as you start to feel the flames get hotter and hotter: you continue to hear the pleasant, mildly cheerful piped mood music direct from Muzak’s New York office. For some people reading this, these events would be literally their idea of hell, with the Muzak just the (poisoned) icing on the cake of shit that is being stuck on a very tall building in New York after a plane has just crashed into it.
And so, if this is your idea of The Bad Place, all of the above happened on July 28th, 1945. The New York Times’ front page story the next day noted how the Muzak never stopped as the flames raced up and down the elevator shaft, damaging cables:
Even at this terrifying juncture, however, the 'canned' music that is wired into the observatory continued to play, and the soothing sounds of a waltz helped the spectators there to control themselves. There was no panic, but within a few minute, the heat and choking fumes from the fire below made the observatory uncomfortable.
One thing to remember about elevators in the late 19th century and the early 20th century was that people were terrified of them. The idea of being quickly whisked high in the air in a metal box was not some TARDIS fantasy, but was instead something that might lead to them plummeting to an early death. Thus the reassuring presence of the attendant, in some ways basically there to reassure the easily spooked public. But as the public became more used to the idea, the lift attendants gradually started to get replaced by mood music supplied by the company Muzak.
Muzak’s business model was founded on wires. Because Muzak produced their own recordings and manufactured their own records (they were an early adopter of 33rpm vinyl records), and played them over a network of wires connecting them to the businesses who wanted their product, the sounds heard over the speakers were apparently pristine, unaffected by the vagaries of radio transmission. From Muzak’s perspective, elevators was a relatively small part of their business from the 1930s to 1950s, but essentially, if you could get electric light into an elevator, you could get Muzak's cabling and a speaker into an elevator. They piped their music into department stores, factory floors...anywhere with a manager who believed the mood needed improving, essentially.
The continued presence of Muzak during an emergency like the one on July 28th, 1945, was still novel enough for the New York Times to find it worth commenting on; the early 1940s was Muzak's biggest boom years. In 1939, they supplied music to 399 businesses, and five years later the amount of businesses receiving the sweet sounds of elevator had more than tripled. So yes, if Captain America was hanging around the Empire State Building on July 28th, 1945, trying to find a way to save the people stuck up in the observatory - he very likely would have heard elevator music.
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