It was one of the most astonishing images to come out of the war. At 6:47 P.M., 13 minutes before the Feb. 23 deadline set by the U.S. for Iraq's withdrawal from Kuwait, sirens sounded over Jerusalem, signaling a Scud missile attack. Inside the sold-out 800-seat Sherover Theater, the ominous warning clashed with the refrains of a Mozart concerto being performed by the Israel Philharmonic with renowned American violinist Isaac Stern. The orchestra left the stage, but the audience simply donned gas masks and stayed put. Moments later the 70-year-old virtuoso returned, his own mask cast aside, and for seven minutes he filled the tense concert hall with the stately notes of a Bach saraband. "I felt some people having trouble breathing, and this sense of unease," Stern recalls. "So I went out and shushed them down." The Russian-born artist has long been known for his humanitarian gestures, but this was his most singular solo. "I was so moved, looking out over that sea of masks," he says. "It was surreal." As he played his final note, the all-clear was given, only to be drowned out by a thunderous standing ovation. "The gas mask is temporary, but the music I was playing will go on," he says. "That's the only reason one does this."