You're right. No one should be inside any building with a large span roof in a wind storm like this....domed stadium, theater, gymnasium, roller rink, etc. The chance that the entire roof will cave in is very high. A building where the roof is supported at many points by a forest of columns or interior loadbearing walls is far preferable.
What bothered me in reading the description of the construction was each part was dependent on the others to remain stable. THAT bothers the living daylights out of me.
I mean these poor, poor, bastards leaving their homes which are below sea level to go to the only structure that they are praying will weather the hurricane.
They always say that if you're taking shelter from a tornado you shouldn't be anywhere there is a large span roof . . . the wind speeds might not be as high as tornados in this case, but will last much, much longer!