Turn left. Start off by making a jump towards the horizontal pole (#1). Before you decide to move any further, position yourself on a pole. You will have to reach a nearby rope. Once you've managed to do this, start swinging towards the opposite corridor. You may proceed to the next section. There's a slipway here (#2). Start sliding down. Be careful! You will have to make a jump in order to avoid a new group of cables.
I would recommend that you make a quick stop. Enter the Accurate Aim mode. This time you will have to aim at the huge fan (#1). Thankfully, you should be able to destroy it without any problems. Once it's gone, start moving forward. There are some new cables ahead. You should be able to reach a second slipway very soon. DON'T use it just yet. Instead, use the guns to destroy the new fan (#2). Slide down (you will have to avoid some cables along the way).
There are some similar moves ahead of you. Make a single jump in order to avoid the first group of cables. Now you will have to make a dive roll (#1). Turn right. Once again, you will come across a slipway. Start sliding down (don't forget to jump over the cables). You will have to make a new jump near the end of the slipway. Thanks to that, you'll reach a metal pole (#2).
Start swinging on the pole. Now you will have to make a double jump. Thanks to that, Lara will use the grapple (#1). As you've probably suspected, you will have to reach an opposite ledge. I'd recommend climbing down a little. Otherwise you might have some problems with that. There's a last fan ahead of you (#2). Destroy it and use the slipway to reach the new room.
This is one of the most frustrating rooms of the whole base, mainly because there's not too much light here. Start off by turning left. You will have to climb up to the stone platform. From here, you should be able to reach a new ledge (#1). A second jump will require you to reach a nearby platform. Start running forward. Make a single jump towards the new platform (#2). Turn right.
Now you will have to make a jump towards a small rope (#1). Once you're there, wait for a few seconds. A huge tank should fill the generator with a much needed fuel. You will have an opportunity to watch this during a short cut-scene. Return to the ground floor. Stand in front of the generator and use the grapple (#2). Start pulling the rope towards Lara. Thanks to that, you will activate the generator.
Finally, you will be able to take a closer look at the new room. Once you're ready, head on to the next corridor. You will have to use a nearby door (#1). There's some deadly gas in the new corridor. You must avoid green clouds at all costs. As you've probably suspected, you will have to use upper platforms and horizontal poles (#2) in order to reach the opposite end of this corridor safely. There's only one path leading to your destination, so you can't get lost.
You will have to reach a rope at some point (#1). I would recommend that you get ret ready for this jump, because it's quite difficult. If you miss the rope, Lara will end up inside a deadly cloud. Use the rope to reach the new platform. Turn right. Continue making new jumps. You should be able to reach an upper platform very soon (#2).
As you've probably noticed by now, the metal pole is electrified. You will have to wait for the right moment to make a move. You must reach the opposite end of the pole (#1). I would recommend that you start pressing the E key along the way in order to speed up Lara's movements. Once you're at the end, make a jump towards the new platform (#2).