In terms of a skydiver’s body or a formation we need to present the flying surfaces into this relative wind to be stable and start flying. Imagine that your hand out of the car window is your body leaving the aircraft and your palm is your chest and belly, you will need the palm facing the front of the car in order to efficiently catch the wind. 10-12 seconds later, you accelerate with gravity to our ‘terminal velocity’, the point at which you maintain a constant speed (unless you change the surface area or aerodynamics of your body). Terminal velocity is due to the drag created by your surface area as you fall through the air. As you approach this point the relative wind changes in its direction until you feel it from directly beneath you.
As working time is 35 seconds, the 12-second period on the hill is a third of the time you have to score points. It's obvious how important this part is. Competitions are often won or lost by a team’s performance during the exit and just out of the door. The world’s top teams use wind tunnels for training plus a high volume of real skydiving, perhaps 1,000 jumps a year. I’m no expert but I imagine that the engineering to create an exit-simulating tunnel would be extremely difficult. If you want to be a great skydiver you have to skydive a lot!