TroyHeinrich Medicus joked with friends that at the age of 95, he's finally coming out of the closet.On Tuesday and after considerable trepidation, Medicus was to appear at a news conference as the previously anonymous donor who gave $10 million to St. Peter's Health Partners, the largest gift in the health organization's history.The gift will be used on a new five-story patient pavilion and parking garage at Samaritan Hospital on Burdett Avenue, just across the street from where Medicus, a retired professor of physics at Rensselaer Polytechnic Institute, lives in a retirement community.