In high school, I was (literally) a spear-carrier in a production of Aida in which Vickers sang the part of Radames. I remember standing in the wings only a few feet from him in the second act, watching him struggle with congestion just before he exploded onto the stage in full, powerful voice. It taught me so much about the courage necessary to perform at that level.
thanks. Great story!
Tidbit: He was a Christian Scientist and refused to perform Tannhäuser because considered the opera blasphemous.