pika/v2.1/text-to-video Prompt: A dim hospital hallway with peeling paint and flickering fluorescent lights. At the far end, an old gurney slowly rolls forward on its own, squeaking loudly. A pale, eyeless face rises from beneath the sheet, grinning impossibly wide as its mouth stretches open far beyond human limits. The lights cut out for a split second, and when they flicker back, the gurney is inches from the camera.