They're moving closer, someone stumbles, mutters; Their words and laughter scuffle, and they're gone
action, ambiguity of the 3rd p pronoun and someone.
sibilance - mystery, pace, tension, anxious.
their words/laughter - more passive.
irony, they are closer and interacting among themselves but simultaneously they disappear and cut off any interaction with the hider.
gone - struggle of the hider having to stay in one place but he is still excited to win the game.
stumble, mutter, scuffle - assonance and unity of their movements against the hiders isolation and emphasises their scheming.