What is the misunderstanding between Bruno and pavel about the phrasepractised as a doctor?

In "The Boy in the Striped Pajamas," Bruno misunderstands Pavel's reference to being "practised as a doctor." Bruno naively believes that Pavel's past as a doctor means he is still a respected medical professional, not realizing that Pavel is now a prisoner and forced to serve the household. This highlights Bruno's innocence and lack of awareness about the harsh realities of the concentration camp, contrasting with Pavel's grim circumstances.