Turn around and approach the edge. Jump to the ledge below and go to the right. Jump above the toxic water to land on the next ledge. Approach the left side of the ledge. This part is closer to the opposite walkway, so jump to grab it and pull up.

Be careful of the opening ahead! Walk around it, staying close to the edge.

If you approach the edge where the walkway is broken (inside the yellow rectangular of the above screenshot), a situational adrenaline will begin. Natla will fly from above and throw a fireball at you. The camera does not help a lot and you may fall into the toxic pool as you try to jump away.

Go around the opening in the walkway and jump to the next ledge below. Go to the other side.

Then jump to the next two ledges.

Jump to grab the walkway ahead and pull up. Turn right and enter the alcove with the glowing symbol. Grab onto it and push the stone panel forward as much as you can.

Climbing back to the middle level - Stay inside the alcove and perform the Chimney Jump to grab the handhold on the left wall.

Traverse to the left and jump up to grab the next two handholds above. Traverse to the left around the two corners and pull up on the rectangular ledge.