This is a 1952 ad for the engine-driven BN52 model Mobil Directo air raid siren, which used a 25HP Wisconsin air-cooled engine to drive both the chopper (the noisemaker) and two belt-driven pulleys to spin the siren around. Later BN44E models would switch the engine to an electric motor. It was one of the first rotational sirens, and would later redeveloped into the "Allertor" and "Penetrator" electric sirens.
But the videos they showed us in school told us that when we see the flash, we should get under our desks, and those will save us from the blast and radiation!
Surely those videos are factual and realistic, and therefore everyone should have had ample time to get under their desks?
Ah but maybe they didn't have a wooden school desk to hide under. That was the real issue.
So yeah, I guess if they had adequate warning, they could sprint to the nearest school and try to cram under the nearest desk