They were willing to pay the ultimate price to help the people they'd come to love. March 15, 2004?Carrie McDonnall and her husband, David, had just spent the day surveying refugee camps. They were in a hurry to reach the safety of their home before nightfall. Suddenly, the crowded street they were on became eerily quiet. And then, out of nowhere came an explosion of bullets and shrapnel . . . Within hours their tragedy was all over the news. But...