Pip is on the stagecoach and sees two convicts riding as well. Pip instantly recognizes one of the convicts. He was the convict that gave Pip money when he was a child. Pip learns from the two convicts, that the convict that had told his friend to give the money to Pip, was eventually caught and served with a life sentence. Pip hurries to get off the stagecoach before the convict can realize who he is.
Pip is trying to pretend that his life is great. He wants everyone to think he is a gentleman. He is even rude and disrespectful to Joe, who was the closest thing to family that Pip had. Pip doesn't want anyone to realize what his circumstances were as a child. He is ashamed. He tries to convince himself that he is doing the right thing, but by seeing and hearing the convicts he now realizes he is no better than they are.
"All other swindlers upon earth are nothing to the self-swindlers, and with such pretences did I cheat myself. Surley a curious thing. That I should innocently take a bad half-crown of somebody else's manufacture, is reasonable enough; but that I should knowingly reckon the spurious coin of my own make as good money! An obliging stranger, under pretence of compactly folding up my bank-notes for security's sake abstracts the notes and gives me nutshells, but what is his sleight of hard to mine, when I fold up ,y own nutshells and pass them on myself as notes!"
This quotes is showing us that Pip is now starting to realize his own mistakes, and is finally ready to make up for them.