In order to get the Leave No Trace achievement, start the track On the Ice, which is the only track in Antarctica. Play through the track until you get to checkpoint 10 and bailout backward through the hole in the container to activate the secret lab. Then hit the reset button (B) and proceed to checkpoint 12, which is on a forklift. Simply back into the secret entrance on the floor and play through the secret lab dodging the lasers. At the end you will net a Squirrel and the achievement.