It was midafternoon on January 15, 2019, and Christian Craighead was stepping out of the shower. The forty-three-year-old British special-ops soldier was at home...

It was midafternoon on January 15, 2019, and Christian Craighead was stepping out of the shower. The forty-three-year-old British special-ops soldier was at home in Kenya’s bustling capital city of Nairobi, having recently arrived in the country to train units of the Kenyan army.Then a local friend called, saying the upscale hotel and office complex he was at was under a terrorist attack. Within minutes, Craighead was in his pickup truck with his weapons case beside him. He floored the accelerator, steering to the wrong side of the highway to dodge oncoming vehicles and pedestrians.For the next twenty-two hours, Craighead relied on every bit of his twenty-eight years of elite military training to win a...