what do you learn about pip from his encountrs with the convict on the marsh?

Pip is generous to the convict. He takes the food and the file, and is concerned about the 'young man' that Magwitch threatened him with. Although Pip is in fear of his life he is also thoughtful and polite.

We also see Pip's incredible imagination as he imagines his theft of the food from the pantry being called out by the floorboards, and the ghostly gibbet threatening his future.