Why does David think of the man calmy and dissappointed, and why does he still obey him?

David is far from the man (the commandant) and the camp... he can think of the man calmly because he no longer has to fear him. David obeys the man because up until this point the things the man told him have been accurate... no traps.

For the first time since he had arrived in Italy, David could think about the man calmly and dispassionately. He had told him to go north till he came to a country called Denmark. But why should he do what the man told him? Was not he David, his own master, who decided for himself? In the camp, of course, you had to obey the man. He was the commandant, and it had never occurred to David not to obey him. He had seen only too often what happened if you failed to obey even an ordinary guard.