What do you think happens to sam and eric at the end of the chapter?

After Ralph departs, Jack casts his gaze on the bound Samneric. He orders them to join the tribe, but when they request only to be released, he bullies them, poking the twins in the ribs with a spear. The other boys cheer him on but fall silent when they notice Roger edging past Jack to confront the twins. We can infer that he means to do the twins harm.