Brown didn't know precisely what he had come upon in the jungle. But he sensed, intuitively, that Jim was a man with a guilty conscience and was, therefore, pitifully vulnerable. Brown, of course, never expected to confront this sort of man, He supposed that he would have to battle Jim physically for control of Patusan. Of course, he did not tell Jim this. He simply fed Jim's weakness by continuing to speak of their "common blood," the bond between both their minds and their hearts. And at last, Lord Jim walked away, promising Brown either "a clear road or a clear fight."
Cornelius was furious. Why didn't Brown kill Jim? Brown answered that he could "do better than that."
Jim returned and tried to convince Doramin and the other Bugis to allow Brown and his men to return downriver. Doramin was against the idea. Jim then suggested that they call Dain Waris back and allow him to massacre Brown and his men; Jim said that he himself could not do so.
Jim then promised to answer with his life if any harm came to any of the Bugis if they agreed to let Brown and his men leave Patusan. Doramin still did not respond, and Jim told him to call in Dain Waris, for "in this business, I shall not lead." He had to live according to his own code.
Tamb' Itam, Jim's bodyguard, was thunderstruck when he learned of Jim's decision. Jim, in turn, elaborated on his decision: he wanted Brown and his men to be allowed to leave, he said, because that was "best in my knowledge," and his knowledge, he said, had "never deceived you [the Bugis]." At last, most of the men said that they would comply, because, above all, they believed and trusted in the wisdom of Tuan Jim.
Jim realized the immensity of his responsibility. He told Jewel that he was "responsible for every life in the land." Accordingly, Jim wanted no misunderstanding to occur, so he spent the night patrolling the streets. Then he put his own men in Rajah Allang's stockade, which commanded the mouth of the creek. There, Jim intended to remain until Brown and his party passed downriver.
Next, he sent Tamb' Itam, downstream to warn Dain Waris that Brown and his men would be passing, and they were to be allowed to proceed without incident. Tamb' Itam asked for some sort of token so that Dain Waris would know that it was Jim himself who had issued this unusual order. Jim gave his bodyguard the silver ring that Stein gave to him long ago.
Jim then sent Cornelius to Brown, telling Brown to use the full tide in the morning, but to be very careful not to provoke the armed men who would be alongside the river. Cornelius also added that one of the men would be Dain Waris, who had initially pursued Brown upriver. Cornelius then told Brown that he knew another way out of Patusan. Brown was interested; he agreed to take this new, secret route, especially if it would, as Cornelius promised, route him behind Dain Waris. Then, if "something happened," the people would cease to believe blindly in Lord Jim. "Then," says Brown, "where will he [Jim] be?"
In Chapter 42, once Brown has discovered Jim's weak spot, he continues to emphasize to Jim that there is a common bond between them — that they both share some kind of common guilt. As noted above, Brown is similar to Iago — that is, while being the incarnation of pure evil, he is nevertheless very astute in psyching out his opponent. Brown, Conrad tells us, "had a satanic gift of finding out the best and the weakest spot in his victims," and it did not take him long to discover Jim's weak spot. In fact, Conrad virtually uses Jim's earlier words when Brown asks Jim if Jim "didn't understand that when it came to saving one's life in the dark, one didn't care who else went three, thirty, three hundred people," and upon asking this question to Jim, Brown brags that he was delighted: "I made him wince."
Of course, Brown's question uses virtually the same words that Jim used earlier to Marlow when he was trying to explain the confusion aboard the Patna and the fact that any man in an emergency would reach out to save his own life. Thus, we see that Lord Jim's deep compassion, combined with his lingering guilt over the Patna affair, causes him to totally misjudge Brown. Jim's guilt is still so great that he eventually yields to Brown's refusal to surrender his arms, thus leaving Brown and his men with sufficient means to accomplish the forthcoming ambush.
Having now been exposed to Brown's total devotion to evil, we are in a position to know that Jim was wrong in his decision to release Brown, and thus we can once again see how Jim's judgment has been affected by his guilt long before we know of the impending catastrophe.
For example, Jim's defense of his decision to free Brown and his men — "they were erring men whom suffering had made blind to right and wrong" — could so easily apply to Jim himself, for Jim also feels that as he himself once needed a chance to redeem himself, so these cutthroats might also need a similar chance for redemption. Therefore, Jim pledges his life if any of the men should come to any harm — a pledge that later Jewel and Tamb' Itam cannot see any reason to honor.
In Chapter 43, Stein, upon hearing of Jim's releasing Brown, once again calls Jim a "romantic! romantic!" and in this instance, Stein means that the true romantic is forever looking for the innate goodness of man. Jim's altruistic belief in man's innate nobility causes him to be blind to Brown's evilness and thus allows Brown to wreak vengeance upon Patusan.