I had been eating leftover rice and listening to a Miles Davis record someone had left on the break room speaker, when the phone rang. A 35-year-old woman. A “frequent flyer,” the emergency department resident said. I was 3 months into my intern year. The resident sounded bored on the phone, but the patient’s numbers told a different story. I saw a potassium of 6.8 mEq/L and a cardiac rhythm threatening to unravel into chaos. I sprinted down the hall, rehearsing the steps for a cardiac arrest. When I burst through the curtain, I found the patient lying perfectly still.