Sopranos are famous for their temperamental nature, of course, and these days, few are surprised when a big star storms off in a huff or refuses to take the stage until some detail or other is attended to. But soprano Sumi Jo managed to shock even the hardened pros at Opera Australia this week, when she left not only the company, but the continent, in the middle of a run of performances of Lucia di Lammermoor. The singer, who is pregnant, reportedly returned home to Rome on doctor’s orders, but did so without informing the company, the director, or even her own manager. Opera Australia execs found out when Sumi Jo’s hotel phoned up to tell them she’d checked out.