More on the exemptions from going into battle - the Gemara says the order of the exemptions themselves teach us of the proper order of how we should live. Also, the ways one may be fearful in going out to war, and how that's a good excuse, until a certain point if no return. Plus, defining when war is an elective and when it's obligatory. And the implications for other activities when involved in the mitzvah (or war or otherwise). Also, the eglah erufah takes center stage. Plus, a key dispute about which leadership goes out to take responsibility with the heifer and the site that the slain body is found.