The New Yorker provides a glimpse of the world of the Broadway Understudy:
Understudies suffer the artistic frustration of not being able to make a role entirely their own, even should they have the opportunity to perform. They bear the difficult knowledge that their own opportunity for success depends upon the chance of someone else’s misfortune; possibly, they even wish for it. “I secretly wanted to poison the lead I was understudying,” as a columnist for Playbill has put it.