Piotr Beczala, who had gotten terrific reviews for his opening night performance as Rodolfo, lost his voice just before Saturday night’s performance – and Salzburg generally doesn’t hire understudies. So Kaufmann, in town to sing Bacchus in Ariadne auf Naxos the following afternoon, was rushed into the pit (with his supper) to sing the role as Beczala mimed it onstage.