I beleive its the left actually
Anyway on one wall (left or right) there's a set of pipes that present themselves as a slope for climbing up. Walk up that set of thin pipes and on the wall to the right there should be 3 vent openings. Destroy any one of them and climb through, then walk down the corridor and unlock the door to let your team through (make sure you don't go up the stairs before opening the door for your team!)