Short Answer

In Chapter Seven, Bruno constructs a swing and, a couple of hours later, falls off of it. He injures himself, scraping up his knee pretty badly. Pavel, who has seen the whole thing from inside the kitchen where he has been peeling vegetables, runs out to help Bruno. Since Mother is still not home, Pavel cleans Bruno's wounds in the kitchen. He tells Bruno that he used to be a doctor, which confuses Bruno, since he has always just known Pavel as the person who prepares the family's vegetables and waits on them during dinner. Bruno tells Pavel that he wants to grow up to be an explorer. When Mother returns home, Pavel goes back to peeling the vegetables. Mother tells Bruno to go to his room and he overhears her saying to Pavel, "If the Commandant Asks, we'll say that I cleaned Bruno up" (85). She does this to save Pavel from getting into trouble. He is a Jew and not permitted to practice medicine anymore.