"One hour, Colonel. Pre-breathing in fifteen minutes." Ronnie sat quietly. Selena had packed up her computer. Carter put his hand on her arm. "You ready for this?" "I guess so. I've never jumped from this high before." "It's the same but the air's thinner, you weigh more with that pack and you'll come down faster. The tricky part is compensating for wind speed and direction. But you know how to do that. With the GPS you're not going to miss the landing zone. Even though we start high, we end high too. That makes it simpler. Just stay loose and you'll be okay." She nodded. "Free fall for five, then pull the cord. Remember to snap your chin to your chest once you're out and keep your hand on your reserve until your chute is deployed. Keep your legs tight together. The shock is pretty hard when the chute opens. Remember to land back from the balls of your feet." Carter looked at his watch. "We'll begin pre-breathing soon." "Pre-breathing?" "This high, we have to get the nitrogen out of our blood.
