There was a tornado warning for that storm 34 minutes in advance, and the airport staff did tell the passengers in the terminal to "get out, get out" just before it arrived. The problem is that most people aren't always aware of the weather outside and if they're in a warning when in a huge building like a mall, airport, Walmart, etc. Unless you have a phone with a warning app, a portable weather radio, or access to a TV in the building, how would you know that a tornado is bearing down on you? It's a real concern the NWS worries about lately.