In Fat Man and Little Boy, we take a view into the background behind the creation of the two atomic bombs that were used in Hiroshima and Nagasaki. The scientists in the film were more dealt with stress of making this weapon instead of the consequences that would come from it. As the bomb came closer and closer the scientists began to split and separate their views on the project at hand. They took sides either to complete the bomb and put it to use, or to not finish it (or at least demonstrate it and have it not approved). Even after Louis Slotin, a scientist working on the project was exposed to radiation, the project was still underway and completed. Louis later died from radiation syndrome nine days later.
For me, if I was made to research into weapon applications, I would automatically refuse as I would rather find a more helpful way to incorporate my discoveries. Even if it was my only option in the career of science, I'd rather have my research benefit mankind for the years to come instead of causing many deaths to happen.