Let's fastforward folks. Sometime later, we find Jim in a courtroom at an inquest, or trial.
Our man is on the stand, and he's testifying about what happened the night the Patna hit whatever it was that it hit in Chapter 3. He explains that he examined the ship after impact and found a hole. That doesn't sound promising.
The poor Jim starts to ramble, so the judges have to cut him off. Answer "yes" or "no," they tell him. An embarrassed Jim shuts up right quick.
That's when he notices a white man in the courtroom who keeps watching him. Who is this guy? And why does he keep showing up?
As it turns out, this dude is Marlow, who will be taking over the storytelling shortly.