What is ironic about the character of the doctor's assistant, Kolya Vdovushikin?

Kolya Vdovushikin was not a medical assistant at all. He had been a university student of literature when he was arrested. The doctor wanted him to write in prison what he had no opportunity to write in freedom. So the doctor made him a medical assistant even though Kolya knew nothing about it. The irony is of course that he can write as much as he likes in prison writing what he was not allowed to in freedom.