Shortly after ten-thirty in the morning on Wednesday, March 19th, a real-estate agent named Paul Alarab began hiking across the Golden Gate Bridge. Midway along the walkway, which carries pedestrians and cyclists between San Francisco and Marin County, he stopped and climbed the four-foot safety railing. Then he lowered himself carefully onto the bridge’s outermost reach, a thirty-two-inch-wide beam known as “the chord.” It is on the chord, two hundred and twenty feet above San Francisco Bay, that people intending to kill themselves often pause. On a sunny day, as this day was, the view is glorious: Angel Island to the left, Alcatraz straight ahead, Treasure Island farther off, bisecting the long gray tangent of the Bay Bridge, and, layered across the hills to the south, San Francisco.