The fact that Phillip is initially not frightened by the war reflects his immaturity and lack of understanding about what war really is. When the nearby island of Aruba is attacked, he at first is swept up in the excitement of the event. Like much of the populace, he is curious, and wants to see for himself what has happened; like people who converge on an accident site with unthinking and morbid curiosity, he runs down to the shore to see what might be there to see. Phillip has no sense of what danger and destruction is like. He himself feels invincible -
"[he] couldn't imagine that a shell from an enemy submarine would pick [him] out from all the buildings, or hit [him] if [he] was standing on the famous pontoon bridge among the ships."
Phillip's view of war is detached. He knows something about what it entails from what he has heard and probably read, but it is beyond the realm of his experience, and he has no sense of the reality of it.
Phillip's view of the war changes when he witnesses first hand the torpedoing of the Empire Tern." As he watches the ship explode into flames, he says,
"I was no longer excited about the war; I had begun to understand that it meant death and destruction."