The Subway, the Subway Get ready to put away those hard hats and hiking boots. In two weeks, it will no longer be necessary to travel circuitous, and often challenging, routes to navigate North Broadway between the Medical Institutions' dome and the Outpatient Center. For six years, more than 5,000 men and women have kept work going--often 24 hours a day--on the construction of the Shot Tower and Hopkins stops along the MTA's subway system. On May 31, the long anticipated Hopkins stop is scheduled to open, preceded by a day of entertainment, activities and ceremony to mark the occasion. Before then, however, workers must put the final touches on the plaza between East Monument and Jefferson streets, laying cobblestone and brick and planting an assortment of trees, shrubs and ground cover. Although the plaza will accommodate both foot and vehicle activity, university officials hope it will be primarily used as a pedestrian thoroughfare. MTA officials expect about 4,000 new riders to use the subway once the extension officially opens.