But these evocative scenes (their power not limited to Japanese audiences) also contributed to the central dilemma of the story. Earlier, Dr. Serizawa (a haunted figure, wearing an eyepatch because of war wounds) showed Emiko the accidental results of his research on oxygen: an “oxygen destroyer” weapon, which, released in water, would destroy all the oxygen and kill everything. He swore her to secrecy, because he didn’t want others to take his research and use it to make weapons that would be (he said at some point) as powerful as atomic bombs.

It was the central problem of science in the technological era, especially in the development of the atomic bomb. Many of the scientists who worked on it were absorbed in the thrill of discovery, and even many of those who realized they were in a race to make this weapon before Nazi Germany did, believed that the Bomb should never be used in war. They especially felt this after Germany surrendered, and many signed a letter pleading with the President not to use the Bomb against Japan, not only because of moral issues, but because they feared it would start an international arms race that would become catastrophic for the entire world.

By 1954, much of this was public knowledge, as was the case of Robert Oppenheimer, who managed the Los Alamos atomic bomb project, then made his horror of what they had created public, after which he was accused of being a security risk, and his scientific career was ruined. Even a colleague who refused to testify against him, the distinguished physicist David Bohm (who had worked closely with Einstein), was forced out of his teaching job in the U.S. and spent the rest of his career in exile.

After Gojira’s attack, Emiko betrays the confidence of her betrothed, Dr. Serizawa, because of her compassion for the victims. She and Ogata try to persuade Serizawa to use the oxygen destroyer against Gojira, but he resists, believing that as long as he is alive he could be forced to yield its secrets to those who would use it for warfare.

Then they see on television a broadcast of schoolgirls singing a song pleading for peace—much as schoolchildren have done every year on the anniversary of Hiroshima. This causes Serizawa to relent. We see him burning his notes, but we know (even if Emiko and Ogata haven’t figured it out) that he believes this won’t be enough.

In diving suits, Serizawa and Ogata release the oxygen destroyer weapon, and after Ogata returns to the ship, Dr. Serizawa cuts his line and sacrifices himself—not because it is necessary to kill Gojira, but because it is necessary to keep the world free of a weapon “as powerful as the atom bomb.” That’s the message that isn’t at all clear in the U.S. version.

We also saw earlier how upset Professor Yamane was about the plans to kill Gojira, before it could be scientifically studied. But this wasn’t the usual naïve scientist riff—he wanted to know how Gojira survived all that radiation, and how it changed him. The movie ends with his warning, that other Gojiras were possible, and they still did not know how and why this beast survived the H-Bomb, so if nuclear tests continued, the world was in even greater danger.