The piano had extra keys and I was fine with it

I'm on stage and the piano has three extra keys at the bottom — not lowered, just deeper, like someone added a whole octave that shouldn't exist. The piece is going perfectly, but every time I reach for the lowest note I touch one of the extra keys instead, and the sound is just air, warm air, like a heater kicking on. No one in the audience notices. The house lights are up, which is wrong, but I'm not worried. I think I keep playing past the end of the piece because it feels better than the silence that's waiting after it.