At this time, Ralph and Jack are involved in an argument about what is more important on the island. The two boys obviously do not share the same view. Ralph is concerned about safety and security, especially of the littluns since they have been terrified by what they call the 'beastie'. The shelters will also provide protection against the weather. Ralph is exasperated at his ineffectual efforts at building proper huts, since he is not getting much support from the older boys, especially the hunters. They go off with Jack and on return, rather go swimming than help build the shelters. The littluns are helpless and are of no benefit in his attempts at all, they play and eat fruit all the time.
Ralph is also frustrated by the fact that Jack and his hunters are not performing one of their primary duties, creating a proper signal fire and sustaining it. Ralph knows that keeping a signal fire going is their only hope at rescue. Jack, conversely, seems to have forgotten all about rescue. He has become obsessed with hunting pigs, but more importantly, killing one. He even states that before he's rescued, he wants to catch a pig first. It is pertinently clear that hunting has become an obsession with Jack, for even during their argument, he becomes distracted and, when they are on the beach looking upwards at the trickle of smoke created by the fire, Jack is suddenly inspired and his exclamation "Got it!" relates to where the pigs go to in the heat, whilst Ralph thinks he has seen a ship.
At this point, Ralph is overcome with indignation, for Jack is clearly not interested in what is most important. Ralph feels that Jack is having all the fun going out hunting whilst he has to struggle, assisted only by Simon, to build the shelters. He declares:
"And I work all day with nothing but Simon and you come back and don't even notice the huts!"
"I was working too--"
"But you like it!" shouted Ralph. "You want to hunt! While I--"
Both boys are overcome with emotion and become acutely aware of how they rub each other up the wrong way. Ralph has made his point: Jack does something which he enjoys whilst he has to do a difficult task and his efforts are not even being appreciated. He feels taken for granted and the fact that he does not finish the sentence suggests that he is too overwrought to say anymore. The point has already been made.
If one should attempt to complete the sentence, it might read: 'While I have to do the really hard and unpleasant task of building the shelters, which is no fun at all!'
In chapter 3 on page 61, in my edition, Jack and Ralph are arguing about what is more important, shelter, fire, or meat. Ralph says,"I was talking about smoke! Don't you want to be rescued? All you can talk about is pig, pig, pig!"
"But we want meat!"
"And I work all day with nothing but Simon and you come back and don't even notice the huts!'
"I was working too-"
"But you like it!" shouted Ralph. "You want to hunt! While I-"
They faced each other on the bright beach, astonished at the rub of feeling. Ralph looked away first, pretending interest in a group of littluns on the sand.
There is no ending to the quote "While I-" Ralph stops before he finishes the sentence. he is saying Jack likes to hunt, but he does not like having to be chief. He doesn't like having to be responsible for the fire, and the huts and the kids. He doesn't say this, but we can infer it.