well well well, considering they are talking about a mass casualty - most likely a drill where they wear makeup and fake injuries. Hospitals run them yearly with a local city/county.
When I was stationed at a naval hospital in a foreign country, we worked with the local schools/city to transport mass casualties due to a simulated earthquake. Had over 400 beds occupied by children and teenagers in costumes.
I remember it well, considering one of my buses broke down.