You're driving along on a road trip and your engine starts to smoke. You give it another half mile or so, then pull over. By the time you pop the hood, the smoke has turned into actual flames spewing out of your car somehow. So you back away as far as you can for your own safety. It's terrifying enough if this happens to you while driving down an everyday country road or rural highway. But what if it happens when you're in the middle of one of the longest highway tunnels in the world?