The crimson Stain in the sunlit Classroom

"I was sitting in a sunlit classroom trying to take an exam with a dull pencil that kept snapping, while everyone around me was wearing bright yellow raincoats. When I stood up to turn in my paper, I looked down and saw a dark crimson stain spreading across the back of my white jeans, soaking through to the light wooden chair behind me. I felt this sudden, burning wave of embarrassment hit my chest, and I frantically tried to pull my jacket down to cover it, but the sleeves kept shrinking until they were just scraps of ribbon. I looked around to see if anyone noticed, but the classroom had vanished and I was walking barefoot along a cold, tiled corridor in a museum, leaving dark reddish footprints behind me on the white floor. I tried to wipe them away with a paper napkin, but it turned into wet flour in my hands, leaving me standing there completely lost, staring at my hands while a quiet crowd of strangers walked past."