Why did lt. kolter leave in boy in striped pj's

“Young man,” said Pavel (and Bruno appreciated the fact that he had the courtesy to call him ‘young man’ instead of ‘little man’ as Lieutenant Kotler had), “I certainly am a doctor. Just because a man glances up at the sky at night does not make him an astronomer, you know.”

In an effort to defeat his boredom, Bruno creates a swing out of an old tire and a tree just outside the house. He soon falls, and hurts himself. Pavel, one of the new butlers at Auschwitz, runs out of the kitchen and takes the injured boy inside to clean up his scrapes. Bruno insists he must be taken to a doctor, but Pavel tells him he will be just fine with the bandage he has made. Bruno argues that Pavel cannot know this since he is not a doctor, and Pavel says he used to be one.

As a prisoner of the Nazis, Pavel has been captured from his home and career as a doctor to serve Father, his family, and the Nazi soldiers that visit. Able bodied Jewish men and women from every profession were forced to work in labor camps; the young, old, and those who could not work were often immediately killed. Boyne once again emphasize's Bruno's innocence by showing that he has no understanding as to why someone who is trained as a doctor would peel his vegetables and serve dinner. Bruno has been taught that the prisoners at Auschwitz are "not people at all," but this idea doesn't seem to fit with what Bruno now learns about the intelligent, friendly Pavel.

the rhetoric device being used to persuade the audience is pathos.