Yeah, consider 10,000 people in a building when power is lost and all that's left is the emergency generator - which runs on diesel fuel, and probably has a relatively short (hours) supply. This assumes the generator is not damaged or destroyed by either wind or innudation, and the electrical panels and distribution system in the stadium isn't located down low where it is subject to flooding and subsequent short-circuits. Oh yeah, the dome has no outside light entry, so when its dark, its REALLY dark. As in CAVE dark. Once the diesel quits all you have left is the battery-powered emergency lights.

Now add to this the loss of lift stations and water pressure into the stadium. You now have 10,000 people in a stadium with limited electrical power, no toilet facilities, and hundreds of thousands of gallons of fetid water on the field.

It certainly beats being in a building that is knocked flat and then innudated by 20' of water.... but I wouldn't call it an ideal place to evacuate to!