The cop with the pacemaker was shot inside the dome, meaning his killer must be inside it as well. If the dome really is dangerous, well I doubt they'd keep one of their own on the inside to perish with it. So it's a setup. For who knows what, but maybe not something that will affect everybody.
To me, this show reminds me of Persons Unknown. That was an experiment about free will and behavior modification. It is easy to see how dropping a dome can also function as a psychological experiment as well.