In northeast Kenya, schools have increasingly become sites of vulnerability rather than places of learning. For teachers serving in isolated communities under the shadow of extremist violence, each day brings a calculation between duty and survival. That tension turned fatal on Jan. 26, when Stephen Musili, a teacher at Halugho Primary School in Garissa County, was killed in a targeted attack by the al-Shabab militants. Musili, 35, was not unknown to danger. Family members and colleagues say he had lived with threats for years, continuing to teach despite repeated warnings and intimidation.