I dreamed I was singing an opera inside a giant filing cabinet

Every drawer was a voice — sopranos up high, basses down below — and when I pulled one out to use it, the whole row slid out too, and I had to catch them before the music fell out. My hands were full of paper and vibrato, and the conductor was just a little lamp on a desk, nodding along. Woke up still trying to hold the top note.