SEATTLE, Dec. 28 — The Boeing 737 was just reaching 10,000 feet in its flight from Washington to Los Angeles, and the flight attendant told passengers they were free to move about the cabin.

Suddenly, a bearded man in a flannel shirt stood up, holding a box and shouting: "Everybody listen to me! I have a bomb. Do exactly as I say and no one will get hurt!"

Passengers panicked and prayed, but what happened next on this fictitious flight, which unfolded in a simulated cabin on video screens in a two- story office building in Seattle, depended on the reactions of a sky marshal on board.

Respond one way and the situation can be brought under control. Respond another and things quickly spin out of control, said Greg Hoover, a former SWAT officer in Los Angeles and now director of training at the company that designed the program.

"You get stabbed in the front and you get stabbed in the back," Mr. Hoover said, "and multiple terrorists have taken over the plane."

http://www.nytimes.com/2001/12/30/national/30MARS.html