If your speech goes wrong in front of a crowd of people....Remember....
"YOUR THE ONLY ONE THAT KNOWS!"
Just carry on as though it is part and parcel of your speech!
My friend was teaching the theory of Hypnosis to a University Campus and the subject (as she put it) was borning. During her slide show, a picture appeared of her in her bikini on the beach much to the audience's uproar.
She turned and said "now I have your attention and you're awake..." and carried on as though it was part of the presentation.
Inside she admits she died, but no know knew it wasn't meant to be there!