Whats going on is a properly waged campaign against Bahrain to ensure as much economic and publicity damage on the country as possible.
Bahrain, like most GCC countries require massive investment to sustain its current level of growth and a lot of foreign help in the form of labour and expertise. The protestors and their leadership and those running the show (and if you haven't figured out who is running the show just think about all the many times you've gone running yourself), and what you have is a well orchestrated campaign to grind down the government slowly and surely. This latest attack was just one more part of the war in order to scare westerners out of the country.
I was watching a group of protestors the other day, they mustn't have been more than 15 or 16 and they were very well organized, they had spotters checking for police, a lead group of girls to check for police as well, and they were always together, they knew when to turn and run and when to make noise and when to stay quiet. The point is that the whole show is being run in an organized manner and the protestors are being trained for the purpose.
After the air show they started trouble on the airport road as they knew this would have maximum impact on those driving back to catch flights, and they also ensured that there were lots of tires burning throughout the airshow so as to make a bigger visual impact.
Don't believe that these are an unorganized mob with little to no structure or focus, its actually quite the opposite.