“A Cabal scout team is heading for the rupture. Track them down to find a possible portal to Oryx.”
“Track the Cabal” is an objective in the mission Enemy of my Enemy in Destiny: The Taken King
Head out of the terminal room and go around to the left. You need to head back through a portion of the Dantalion. On the left, in the first hallway, you can find a portion of the Cabal systems you can scan. Do so then head straight through the hallway. Go up the ramp in front of you and follow the path upwards. This will lead you to the part of the ship that connects to the Mausoleum of the Dreadnaught.
Turn to the left when you reach the next room. Look forward and you will see a raised door. Just approach it and it will lower itself. Go outside and get ready for a run.