"Why did they stage this in front of everyone"

That's the only way it becomes "real" to people. You have to make the public a corroborating witness.

If a magician tells you he did an awesome trick backstage, then it doesn't have much effect does it? It only becomes "real" when the audience watches and confirms to each other that they all saw it happen.

Same with seeing a bunch of lights, smoke-effects, stage props, fake-blood makeup, and a bunch of emergency uniforms everywhere. A very simple illusion, but it seems to work well enough.