Why is surprising and humorous in a dark way when Jack says, "I'm not going to play any loner. Not with you." ?
In William Golding's Lord of the Flies, Jack's statement about "not playing" after the very tense tribal meeting is humorous and surprising in a dark way. Consider what has just occurred: Jack has fought with Ralph over the role of the hunters and called a new vote for Ralph not to be chief. Nobody speaks out; instead "under the palms there was a deadly silence" (127). When Jack asks a second time for anyone to speak out against Ralph, "the silence continued, breathless and heavy and full of shame" (127).
Jack has found his support in this tribal meeting sadly lacking. Deeply embarrassed and full of shame, he has "humiliating tears[...]running from the corner of each eye," and in this moment, Jack announces his intention to leave the tribe. In what could have been a powerful moment, Jack's words rush out silly and childish--"I'm not going to play" (127). This is the equivalent of the childish 'I'm taking my toys and going home' statement. It's humorous in the way his words break up the overly tense mood of the scene; Jack's reference to 'playing' as if everything on the island were some grand game.
This is a profoundly dark moment in the novel, the sudden rift between the two leader figures among the boys, but Golding tempers this scene with a dose of reality, Jack's childish outburst, reminding the reader that these are only boys, only children after all.