58 fatalities, over 500 injuries and a lifetime of nightmares. Two survivors of the deadliest mass shooting in U.S. history narrate their overlapped stories from the night that forever changed their lives. For Royce and Darla Christensen, what was supposed to be a casual shift with a security company on the last leg of the three-day Route 91 Harvest Festival in Las Vegas quickly turned into a life-altering traumatic event, forever remembered as the Mandalay Bay shooting.