The Mayor Trolley Problem

There's a runaway trolley, about to kill five workmen on the track. The righthand track is a dead end, unused in ten years. The mayor has set up picnic tables on it and invited convalescents at the nearby City Hospital to have their meals there. In the words of Thomson, "guaranteeing them that no trolleys will ever, for any reason, be turned onto the track." Only one convalescent has arrived yet, he is there because of you and your promise alone. Do you kill him, or let the five workers die?