Can you really make a fountain/firework show darker? By their very nature fountains are very fluid and flow, they don't do shock or dark, they mainly look whimsical. And fireworks aren't really a shock factor... Whilst I imagine the movies they use on the water screens could be darker I just can't imagine a dark spectacle, because by their very nature they aren't really shocking.
If they had a few spare scare actors you could get a cheap shock. But I can't imagine that happening.