Go North and remember to stay clear of the blazing elements of the surroundings and water (Garret cannot swim). Approach the moored boat and use the blackjack in the spot in which it is tied to the jetty. This action will result in detaching the boat, which will float several meters to the south. Go there and use the fact that you can reach the boat and reach the planks to the West. Proceed on and make sure that you have full Food supply, which may come in handy in several minutes.
Quickly, walk over the successive wooden planks and get off them, before they detach from the rest of the structure. Approach the big scaffolding to the South now and start climbing. Towards the end of the climbing, grab onto the rope, climb up and jump over to the small balcony. Turn right and use the claw to make it over to the window above, and walk into the blazing building [Auldale Bridge - Market Street].
While exploring this building, you need to act fast, on the one hand, because Garrett will experience respiratory problems here (gradual declining of the health bar) and flames will start to appear. On the other hand, however you should not haste too much, because there are two items around. On the left, there is a Candlestick - 15G, and inside the locked chest, shown on the screenshot, there is a Watch Medal - 30G. I recommend that you use Focus here, thanks to which Garrett will be able to break into the chest much faster. If you cannot use Focus, you should start running early enough and try not to make any mistake while using the lockpicks. After you obtain both of the items, escape the building.
After you are back in the open, wait for a part of the wall, of one of the buildings, to collapse, climb onto the crate and use the claw to make it over to the ledge above. In total, you need to take three jumps here. First, jump to grab the rope and, after you climb onto it, jump to the other rope and finally, jump to reach the window on the next building. Auldale Bridge - Watch Junction]. Quickly go Southwards (your character will have problems breathing). Jump to the rope, turn by 180 degrees and, after you climb onto the rope, jump over to the higher level of the building. Go straight ahead here, squeeze under the collapsed part of the roof and interact with the turning wheel to secure safe exit for yourself, from the blazing trap.
Garrett will soon start to run over rooftops of the blazing buildings [Auldale Bridge - Rooftops]. If you want to avoid falling through the rooftop of the nearest building, walk over its right side. Fortunately enough, even if you fall inside, you will be able to get out by hitting the interactive mechanism with the blackjack. Regardless of what happened, collect the Ashtray - 3G from the small balcony and use the claw again. Turn left here and start running, jump over the missing elements of the wooden plank.
Turn right and try to walk over the next rooftop. After Garret falls into the building, [Auldale Bridge - Watch Junction], rush towards the only exit, as quickly as possible, in order to avoid losing health points. Get to the passage marked by the game, which you need to squeeze through [Auldale Bridge - Drawbridge]. Take several steps to the West, which will start a cutscene Once you regain control over Garrett, start running to the West. Run over the metal element of the drawbridge and take a leap [Auldale Bridge - Foundations].
Walk into the next area, turn Southwards and then Westwards. Run over the wooden plank and jump to its next part. A bit ahead, you will have to climb a little. After you get to the very top, you will have to be fast, because your character will have problems breathing, again. Quickly, cross the area filled with smoke (watch out while walking over the narrow beam and crouch to avoid flames) and reach the building's exit. After you are back into the open, go towards the building in the South-West, which will soon collapse. Quickly, use the claw on the wall to the right and reach the exit point, which will end this exceptionally long chapter.