Keep moving forward to survive

After Lara has been knocked out down at the beach, she comes to tied up, hanging upside-down from the ceiling. To escape, start swinging sideways, left and right, to gain enough momentum and push the neighbouring sack into the burning torch on the altar. It catches fire and falls to the ground. The sail on the wooden beam on the side catches fire as well. The camera has turned. Start swinging sideways again - which will this time direct you towards the burning beam - to set your sack on fire. This will free Lara, but she's hurt by the fall. You need to pull out the metal rebar now stuck in her side. To do so press the shown button (action; PlayStation: Square, Xbox: X) repeatedly till it's out. Then head into the tunnel, towards the burning light.

In the next cave you discover an unfortunate victim of the scavengers. Grab a torch from one of the two wall mounts either left or right of the next tunnel opening. Follow the tunnel until you come to a blockade. Here use the fire of your torch to burn down the white cloth and thus destroying the flammable barrier. Step through and squeeze through the narrow gap. The water will extinguish your torch. On the right cave wall you will find a little goblet of fire where you can relight your torch. Climb onto the wooden scaffolding on the left side and there use the relit torch to set the white cloth on fire. The flames will make their way over the the blockade and cause the barrel to explode, removing the flammable barrier. The path is now clear. Get down and over to the end to climb up into the opened passage. Sneak into the narrow tunnel. Lara is attacked by the scavenger. Shake him off with the movement buttons and you will escape for now. Crawl further along the tunnel and wade through the water to emerge in a large cavern.

Find a Way Out

Once again your torch is extinguished by the stream of water coming from the ceiling. Take note of the large mine on the left. Head over to the right area. On the right side is another burning chalice where you can light your torch once more. Set the two white cloths on fire to loosen the contraption. (You can also light up the flotsam now, instead of later.) Now the other cage will collect all the garbage coming downstream. Head up the ramp till you reach the first red board. Use this to jump over to the cage that moved upwards. Lara's weight pulls it down and the other cage, with the flotsam inside upwards. The items will tumble into another cage at the top end of the wooden walkway. Get back onto the wooden walkway and run up to the other crate. Set the flotsam on fire. Then push the cage, to send the burning flotsam down the chute, avoiding the waterfall which would extinguish the fire, and towards the mine. A big explosion will ensue. Lara is rewarded with +250 XP.

Escape

Head into the newly opened passage. The left is blocked off by falling rubble so head right. The floor will give out and send Lara hurling down a sloped passage. At the bottom do not wait for falling debris to kill you, instead immediately follow the tunnel and at the end jump across the gap. If necessary, pull up and also jump across the second gap. Once more and you are almost back in another passage. A boulder will fall down leaving only a narrow gap, and here the scavenger is back. Shake him once again and then give him a kick to get rid of him once and for all and earn +25 XP in the process. Flee further through the tunnel. Jump across the last gap and then scramble up the steep slope. When the first boulder comes crashing down, escape to the left. Scramble further upwards. The second boulder is avoided by moving to the right. Continue up the tunnel to emerge outside. Lara is rewarded with +300 XP.

Follow the path to the left until Lara spots a lifeboat.