He argued unconvincingly that they would let him alone, perhaps even make an outlaw of him. But then the fatal unreasoning knowledge came to him again. The breaking of the conch and the death of Piggy and Simon lay over the island like a vapor. These painted savages would go further and further. Then there was that indefinable connection between himself and Jack; who therefore would never let him alone; never.
As Ralph senses the horror of what is happening, he realizes the barbarism to which Jack and the others have descended. All law and order has been destroyed as symbolized by the destruction of the conch which has been used to call the boys to meetings, and, especially by the brutal deaths of Simon and Piggy. Man's intrinsic evil is undeniably present on the island that Ralph has originally imagined as the Coral Island of the British novel he has read. It is this evil nature of Jack, who like Macbeth. would have "blood for blood" and eliminate all his enemies in his maniacal drive for power over others.
In his terror, Ralph understands that there is only one end to his fears: either he or Jack will die. How truly alienated Ralph feels at this moment. In this terrible isolation, Ralph wants to rationalize, thinking to himself that the boys are not as bad as it seems, and the deaths of his friends have been accidents. Nonetheless, he concludes that the boys are savages, after all. Ralph lies in the darkness that shelters him, yet he feels his aloneness because he has become "an outcast."