I bounded over the gray, dusty terrain toward the huge dome of Conrad Bubble. Its airlock, ringed with red lights, stood distressingly far away. It's hard to run with a hundred kilograms of gear on—even in lunar gravity. But you'd be amazed how fast you can hustle when your life is on the line. Bob ran beside me. His voice came over the radio: "Let me connect my tanks to your suit!" "That'll just get you killed too." "The leak's huge," he huffed. "I can see the gas escaping your tanks." "Thanks for the pep talk." "I'm the EVA master here," Bob said. "Stop right now and let me cross-connect!" "Negative." I kept running. "There was a pop right before the leak alarm. Metal fatigue. Got to be the valve assembly. If you cross-connect you'll puncture your line on a jagged edge." "I'm willing to take that risk!" "I'm not willing to let you," I said. "Trust me on this, Bob. I know metal." I switched to long, even hops. It felt like slow motion, but it was the best way to move with all that weight. My helmet's heads-up display said the airlock was fifty-two meters away. I glanced at my arm readouts. My oxygen reserve plummeted while I watched. So I stopped watching.