Call me a pessimist, but I'm betting on evilness.
If the Dome doesn't collapse or anything, they're going to be in the middle of a lake with no power, water, or facilities for who knows how long.
Yeah... it's just a bad situation waiting to get worse.
Makes me think of a few disaster movies or alien-invasion novels... it's all there, the idiocy of officials, people waiting until too late, the last refuge that's going to go horribly wrong...
When Mayor Nagin was talking about what folks should bring with them to the shelters, he specifically mentioned NO WEAPONS. SirKit and I had a big laugh about that. He said it reminded him of Gimli being stopped at the doors of the Golden Hall and being made to give up all his various axes, knives, etc.
It is a good warning in NO, though. It can be a brutal place.