As shown earlier, Braulio blocks his opponent's arm to begin his escape vs the north south position, but when he is unable to complete the turn, he creates space to slide his shin in between him and their arm. Using his shin on their biceps, he creates more space to replace his shin with his foot. Once he has his foot on their biceps, he extends his leg and regains open guard.
Links to other Parts:
Part 1,
Part 3