You are in the main entryway to the Temple. Now you just need to find and kill Capitaine Rose. You can just take to the tops of the pillars and then you have a clear run way straight to the entrance of the Temple itself.
If you want to get through on the ground, you have a lot of sneaking to do. This is very helpful if you want to pull off the Optional Objective.
Arno is behind the group and can move up to them slowly. Clear out whoever gets closest to Arno first just to save yourself some time. Focus on being defensive initially. This will save you a lot of pain. If you are having trouble, drop a Smoke Bomb to stun some of the enemies and get some quick kills to thin them out. You can end the fight at any time by taking out Rose.
Any of the Raiders that survive here will persist into the next objective.