Airman 1st Class Dylan Mosher, an aerospace medical technician assigned to the 28th Medical Group, shows Master Sgt. Nathan Landry, the first sergeant assigned to the 28th MDG, and Master Sgt. Luis Guillen-Diaz, the mental health flight chief and additional-duty first sergeant assigned to the 28th MDG, an electric cardiogram machine at Ellsworth Air Force Base, S.D., June 9, 2017. Guillen-Diaz shadowed Landry as he checked on various Airmen throughout the group. (U.S. Air Force photo by Airman 1st Class Donald C. Knechtel)