When the natural rhythms of our lives are brutally disrupted, we respond with fear, anger, calm, sometimes violence, and often with courage. Katrina was that kind of upheaval. It obliterated towns, submerged a great city, exposed a nation's frailties and prejudices, and uprooted thousands. It also brought forth untold instances of duty and determination. Here are the stories of two men and their colleagues, Gulf Coast residents who, when their world was torn apart one Monday, deftly managed their way through the storm ("Vertical Evacuation" at the Hilton and When a Local Wal-Mart is a Lifeline).