Very much reminds of an exam I had to play in conservatory where my teacher was to turn pages; and so he did, in a long Buxtehude work turning a couple of pages too much not noticing it at first and then searching for the correct one. His remark, just 'huh, that was a bit huch -grin-' ; fortunately I had the piece enough in memory not to make mistakes, but it does get on the nerves ....