You left Kurtis back to the arena and you need to find the Third Periapt Shard in order to destroy Eckhardt. In order to do so, you must find Eckhardt's old lab.

After sliding down, enter the tunnel on the right hand side. You can see a Health Pack behind the gate, but you have to make your way around in order to get it. Reaching the lava pit, you start sliding, so jump to land on the ledge ahead. Walk to edge and hop to the next one, or back up a bit and take a standing jump. You can see a lower ledge on your left, but there is no need to go there. Walk up to the edge and jump directly on the ledge with the lever to get an upgrade in leg strength. Pull the lever to open the gate in front of the Health Pack. Climb on the wooden walkway and follow it to the end. Pick up the Large Health Pack and go back where you started. Now follow the other side of the tunnel.

The timed gate - By pulling the lever, you open the gate at the far side of the room. You can see a couple of ledges ahead from where you have to pass in order to reach the gate. There is an alcove on the left hand side of the room, but there is nothing interesting in there. In order to make it to the gate, you must have got the strength upgrade. This will make Lara land directly on the first ledge beyond without having to grab it and pull on it which is a waste of time. If you have not got the strength upgrade, check above.

First, walk the edge to make Lara say "My legs feel stronger. Maybe I'll make that jump" to prevent her from saying that whilst on your try, because the letters on your screen will not let you see clearly. Pull the lever to open the gate. The camera shows the gate opening, but you can move Lara whilst that. So, after pulling the lever, turn right and start running. The camera returns back to Lara when you reach the edge, so be prepared to jump. Jump to land directly on the first ledge. If you accidentally drop to the ledge beneath the starting position, do not hesitate at all and jump to the ledge ahead. Keep running and jump to grab the next ledge. Pull up and keep running. Again, jump to grab the ledge where the gate it. Pull up and sprint past the gate. If you do not make it, either load your game or shimmy along the crevice on the wall.

[Note - If you are used to the Sprint button, you can sprint on the ledges and jump at the edge of each ledge. This will make Lara land directly on the ledges without having to grab them AT ALL. A very good example has been set up by Simulation. Download a movie and take a look: High Quality (1,8MB) or Medium Quality (280Kb). Thanks to Simulation for providing the videos.]

Area with lava pit - Once you make it, continue through the tunnel to reach another lava pit and go down the steps. Turn left and jump to the ledge with the wooden ladder. Climb up the ladder and then climb up the next one. Cross the bridge and take a running jump to clear the gap and land on the other part of the bridge.

The camera does not help you see the ledge with the lever on the left. If you take some steps back, you will be able to see it. You can either slide down the ramp and jump at the edge, or take a running jump and grab the ledge with the lever. In both cases, make sure you jump from the right hand side. Pull the lever to extinguish the fire from the statues and disable the blades from the steps beneath them.

Hang from the wooden ledge on the right hand side and drop to the ledge below. Face the center of the room and walk up to the edge. Hop on the pillar on the right below you, turn right and continue heading up the stairs. The door opens after lava flows through it. Go through it to end the level.