Tom has pretty much abandoned Joe by this point in the novel. When he wants to play Robin Hood earlier in the novel, he goes out with Joe; now, however, the stronger, more well-defined character of Huck has taken Joe’s place. Whereas Joe and Tom seem to be roughly equivalent characters, Huck is clearly more independent (given his way of life, he has to be) and in certain ways more mature than Tom. Despite his relative maturity, Huck nevertheless defers to Tom’s imagination and initiative when it comes to planning their activities. He does so largely because he is slightly in awe of Tom’s book-learning and his superior knowledge about the rules governing their various activities, even when he does not fully understand what they mean.
Although Huck generally seems tougher than Tom, when the robbers are asleep, Huck is the one who is too afraid to move. This sudden fear may seem out of character, but, in general, Huck’s survival seems the result of his flight from difficulties, so it makes sense that he would attempt to avoid conflict and danger. Tom, on the other hand, tends to confront his problems and attempts to devise clever solutions. In a way, Huck is more of a realist—more likely than Tom to recognize the point at which an imaginative game ends and real life, with its real dangers, begins.
Twain raises the level of suspense by suggesting that Injun Joe may be seeking revenge on Tom and Huck. It is important to note that Injun Joe’s unnamed partner is more of a device for Twain than a true sidekick. It takes a certain level of maturity to develop a true partnership. Tom develops this maturity as the novel progresses, but Injun Joe certainly does not. Injun Joe’s partner serves merely as a device to enable dialogue, which gives the boys—and us—access to Injun Joe’s thoughts. Were Injun Joe alone in the house, there would be no conversation for the boys to overhear. The disclosures Injun Joe makes and the gaps he leaves generate the mystery of this portion of the narrative.
Once the hidden gold is introduced into the plot, the novel becomes more an adventure story and less a realistic portrayal of boyhood. Twain may also have chosen to introduce the hidden gold to provide a grown-up counterpart to the trinket-for-ticket exchanges that take place in the early chapters. Here, Tom’s newfound maturity has as a counterpart a larger, more intricate economic system—one in which there is considerably more at stake.