Why did Karl Jaspers work at the psychiatric clinic without a salary?

Karl Jaspers chose to work as a volunteer research assistant at the University of Heidelberg psychiatric clinic without a salary to maintain his intellectual independence. He wanted to learn the field on his own terms, at his own pace, and focus specifically on patients who interested him, rather than being restricted by the regimented patterns of thought imposed by his teachers. By agreeing to forgo a salary, he secured the freedom to conduct his research in his own time and according to his own methods.1