I love, love, love this! I did something similar with a few voice students for whom distractions during auditions triggered debilitating anxiety. We had a small but very open recital hall space on the upper floor of the studio. I used it to run practice simulations of auditions, sitting behind a desk and glaring at them over my reading glasses. I’d ask them questions like I was a judge reading thru their performance resume, recruit other teachers & their little piano people to barge through like bulls in a china shop, and other staff to come in & hang over my shoulder pretending to whisper questions. Basically, everything I’ve ever had happen at an audition as either an auditioning performer or judge. I’m also big on practicing starting from various places in the music in the event you have to stop & restart mid-audition. (Attended a concerto performance by one of the piano professors where she somehow got stopped & it took a few tries for her to get going from one of her pre-planned crisis points. It was heart-stopping 
) My students are rather used to dealing with accompanist error thanks to my mad piano skillz 
but we sometimes practice that as well.
Being able to relinquish control is such a valuable skill for musicians. And mistakes are just proof that you’re trying!
