Ryan McGarry trained to be an emergency room doctor at Los Angeles County-USC Medical Center, completing his residency at this bustling, high-volume facility. If professional duties weren't enough to keep Dr. McGarry occupied, he also made Code Black, a documentary about the high-pressure world of emergency room docs. McGarry covered the period from 2008 to 2012, which means his film preceded the onset of Obamacare. But this powerful documentary -- which showed at last fall's Starz Denver Film Festival -- accomplishes many things vital to understanding health care: First and foremost, it demonstrates that young doctors are dedicated, eager to help and devastated when they can't. It underscores the loss of collegiality that accompanies a shift from the hospital's old facility to a better equipped new one. That move is accompanied by an increasing demand for paper work that begins to consume the doctors' time and erode their morale. You'll also get a clear picture of what these doctors actually do, and the excitement it can generate for them. It strikes me that working in an emergency room consists of one adrenalin rush after another -- except that physicians can't afford to be swept away by the unpredictable energies of their often chaotic workplace. Slickly produced, Code Black has the pacing and impact of a thriller, but don't get me wrong: This is a ground zero look at health care in a busy urban setting. You will be both amazed and edified, and better able to understand how physicians deal with frustrating wait times, patients without insurance, immigrants and a host of other problems that go a long way toward defining contemporary health care in such a hot-house setting.