When Roger begins to throw stones in "Lord of the Flies", why does he just throw them near Henry instead of at him?

Roger has not yet completely forgotten the rules and laws of his old life in Britain. Note the lines "...there was a space round Henry, perhaps six yards in diameter, into which he dare not throw. Here, invisible yet strong, was the taboo of old life. Round the squatting child was the protection of parents and school and policemen and the law." (pg 65) Roger is so used to the laws that were enforced upon him in his old life, that he has not yet broken free of them to follow his own morals. It is almost out of habit that he does not throw the stones. He probably still feels a bit guilty as well, because in Britain he was taught as a child that throwing stones was wrong.