With the Head of Saint Denis in his possession, Arno is ready to leave the area. Charge relic when you see people coming at you. When they are within the circle around Arno, loose the power of the relic to take them down. Right now you cannot free run so you need to use the stairs. Head straight through the camp. There are a lot of Raiders to deal with but the Relic makes very short work of them. Just get to the stairs going up to complete this objective and the main story for the DLC!