Exercise 4 shows a common sequence with an off course tunnel trap nearby. Many handlers will try to front cross between jumps #2 and #3, but this requires the handler to be ahead of the dog in order to execute the front cross. With an attempted front cross, the handler is driving the dog into the off course tunnel until the front cross begins, so that a late front cross will be disastrous in this situation.
I prefer to use a combination of 3 handling cues:
2. Body turn
3. Rear cross
When you decelerate at jump #2, the dog clearly understand that a turn is coming, and the off course tunnel is NOT the next obstacle to take. As soon as the dog is taking off for jump #2 (their commitment point), rotate your entire body (legs too) and face jump #3 and give your jump command. At the moment your dog commits to jump #3, cut behind them and drive toward the tunnel. Do not wait for them to land; you are free to move at the moment they launch into the air. It is crucial to execute the deceleration BEFORE the body turn–do not do both of these at the same time. You have plenty of time to come to a stop and then turn your body.