No matter how much you eagerly anticipate your first shift in the ED as a medical student, it is also intimidating. For the first time you are presented with a completely undifferentiated patient and asked to come up with a differential, plan, and disposition. No more "Go see the COPD exacerbation in the ED" or "Why does this CT show a case of appendicitis?" Medical school does not train you to think like an emergency physician. Completing a history and physical, then ordering lab tests and imaging, waiting for them to arrive, interpreting them, and finally making a diagnosis and treating the patient is not an option when they are bleeding out before your eyes (or having a stroke, or an MI, not breathing, seizing, possibly bleeding in their brain, foaming at the mouth, loss of consciousness, etc.). In the ED, it is not your job to come up with an iron clad diagnosis, it is your job to rule out life threatening conditions or treat them if they exist. And to do th...