Carl Darnall Army Medical Center (DAMC) or Darnall Army Community Hospital (DACH) on Fort Hood, the only Fort Hood hospital on post. 50628 is the EMS-hospital patch to call in transports. I'm not sure how Fort Hood EMS operates, but Killeen and Cove EMS may use this to give radio reports when they are typically 5-10 minutes away.
Wow, I never ever realized this. Thank you.