Bartle’s guilt about failing to protect Murph’s life shows that he is still trying to feel a sense of control over something that he cannot fully accept as inherently disordered and uncontrollable: war and death. It is the contrast between the elements over which he
does have control (e.g., joining the military, promising to keep Murph safe) and his current state of unhappiness, based on what he
could not control, that confuses him most. His illusion of control proves harmful and dangerous, because it makes him feel responsible for everything that happened and thus turns his hatred, confusion, and rage toward his own self.