The Fear of the World

The movie is built around a quote from the Bhagavad Gita that Oppenheimer was actually quite fond of, which was, now I have become death, the destroyer of worlds. He doesn't realize that he's actually going to potentially destroy the world by setting off a chain reaction that cannot be stopped of nuclear proliferation. But he's also not able throughout the movie, right? What is his belief about the use of the weapon he's developed? And he has a million different defenses for it.