A bit further you will find yourself on the main road. You should see there a big gate. Move close to that entrance and trigger Cooperative Concentrate Mode.
After finishing the massive shooting during the slow-mo you will start a standard fight. Make sure that you will at the first place eliminate guys from the balcony and two opponents on your right (they will not stay next to the main building)
After the victory go around the building and follow your brother.
In that way you will ended up once again on the main road. A bit longer cut-scene will be triggered as well. After watching it you will square up to duel with a boss. You already should know how to act in order to win. Keep your palm close to the gun and make sure that your opponent is in the middle of the screen.
If you are wishing to catch up your woman, go between the buildings, this time on the left side. During covering this part it is worth to hide from time to time behind a building wall in order to eliminate opponents.
Going further you will reach a brick arch and you will reach the market [secret]. In this place a long shooting will start. If you will get full Concentrate Mode, don't be shy to use it (Ray's dynamite treat the same).
In that area you will find the weapon store. Playing as Thomas, you should buy a bow which is one of the most effective weapon in the whole game (because of a short slow-mo every single time when you aim). In the case of Ray, buy some dynamite.
Further way will be showed by our brother. Go down the stairs and turn left, walking next to them. Throughout that moment of the chapter [secret] you will not encounter many foes.
Going further you will reach a more open place. Before you will star extermination, watch a short cut-scene, when a mysterious woman will hide in the nearby church - your another point of destination).
During shooting make use of dynamite (when you keep a dynamite in hand do not make a fuse shorter, distance to cover is much longer than usually). You won't get many places to hide but this fight is not difficult.
As I said before, after killing all your opponents go to the church and enter it [secret].
Being inside you will trigger a short conversation between people who are there. After that discussion start Cooperative Concentrate Mode. During the shooting your opponents will appear for a long time, in center of the area as well as on the both sides (jump over the wall). In order to kill them all, do not leave the church.
After killing all enemies leave the temple and go straight ahead. Some opponents will appear on the roof of the nearby buildings. But before you will try to kill them, friendly backup will help you and the chapter will come to an end.