Tom and Alan
In case you had any lingering feelings that Long John Silver talks a more violent game than he plays, his showdown with Tom proves that his threats are serious. (By the way, this Tom isn't Squire Trelawney's servant, Tom Redruth; this is another guy.) As Jim takes his first walk around the island, he happens (as usual) to be in the right place at the right time. He is hidden in a tree when he witnesses Long John Silver making the pirate pitch to one of the two members of the crew yet to be turned, Tom. As Long John Silver is trying to talk Tom around, they overhear a long, drawn-out scream. Long John Silver assumes matter-of-factly that it's the cry of the second remaining non-pirate crew member, Alan, being murdered.
Tom applauds now-dead Alan's bravery and turns his back on Long John Silver. This proves to be a big mistake. Long John Silver picks up a branch, strikes Tom across the back, then puts two bullets into him. Long John Silver is not fooling around, and Jim and we readers know just how dangerous the old sea-cook is behind his charming exterior.