The convict discloses his real name: Magwitch. Pip, having heard from the night watchman that another person had come in with Magwitch, asks him if this is so. Magwitch claims no one was with him, but maybe he did see someone else there. The topic is dropped. (WHO was that person on the stairs that Pip tripped over?!)
Pip finds out that Jaggers was Magwitch’s lawyer for his last trial in London before he up and skipped out of town to America. “…and what I done is worked out and paid for.” So he owes Jaggers nothing.