Head to the next room and kill the first set of enemies then scavenge their weapons and ammo. There's a lot of targets that will come in here as well. Since you recovered your masks, you'll be able to use Overkill once more. Activate overkill and aim for the doorway in the far end of the room. Enemy reinforcements will arrive through this hallway so it will be easy getting rid of them in one Overkill gauge.
Continue upstairs and kill the enemies in the lower floor. Go upstairs and engage more enemies. Be careful of enemy reinforcements that will enter the room and may catch you off guard and flank you. Continue further upstairs and head to the door to complete the section.