He has the mind of a novelist, he zooms in to great detail and then zooms out to take in the scope of the fighting. Yet when we get this view from afar we see how insignificant they all are in this land while up close he knows they are fighting for their lives.
So why does Smerdyakov kill himself (and Fyodor)? We get a lot of talk all through the novel about how Smerdyakov is a terrible person (stinking, as his name suggests), but isn’t he the most in need of pity? The only person who seemed to show him any respect was, ironically, Fyodor (trusted with the money, sent him to school, told him the knocks). Doesn’t his suicide (off-stage, too) show him miserable and lonely?