Fugitives - Breather
After the escape, you'l reach a dense forest during the daytime. As soon as you gain control of the characters, go down the right most path, jump over a gap, and have both characters sit on the rocks near the cliff's edge. Wait for a small cutscene for both players to unlock this achievement.
This achievement can be seen in the video guide at 2:36:NOTE:
Achievements are only available to owners of the game. Players using the "Free Trial" friend pass will NOT unlock achievements.