Perhaps you should clarify what angle you're trying to get at with this question.

I expect you're raising some version of the "do you value some lives more than others" issue. There are likely at least some people here who would pick Yudkowsky over three unknown people, based on a rational evaluation of expected utility of continued existence. The same issue could be presented by replacing the child with any other person who is expected to have a large positive contribution to the world, such as a promising young surgeon who could potentially save many more than three lives over the course of his career.

Or did you have something else in mind?