As the two convicts are being discovered, they almost turn themselves in because they are being so loud. The search party has the great opportunity of overhearing what seems to be a great fight between the two:
As we came nearer to the shouting, it became more and more apparent that it was made by more than one voice. Sometimes it seemed to stop altogether, and then the soldiers stopped. When it broke out again, the soldiers made for it at a greater rate than ever, and we after them. After a while, we had so run it down that we could hear one voice calling "Murder!" and another voice, "Convicts! Runaways! Guard! This way for the runaway convicts!" Then both voices would seem to be stifled in a struggle, and then would break out again. And when it had come to this, the soldiers ran like deer, and Joe too.
The convicts' noise led the search party to them. As time goes on and discussion between the convicts and their captors, the second convict tries to claim that the first tried to murder him. The second is not Pip's convict, so as Pip reports these details, we almost feel him siding with the first (my) convict.