Tomb Raider Walkthrough Part 51 – Gone Missing, Storm Chaser (Cliffside Bunker to Research Base)
Head through the crack in the Southwestern wall and back toward the Artillery Bunker you passed through much earlier. Look to the right of the Artillery Cannon and you will see where you can rip the wall down with the Rope Ascender.
Go through the hole to the right and look on the ground near the bunker itself. This will lead you to the third Relic (Portuguese Tin Coin). After that look for the nearby rocks. Behind them you will find some sandbags. On top of them is the Treasure Map of the Area. This will let you find any of the items you might have missed on the way in or out.
With all that in hand it is time to head for Shipwreck Beach again. Look toward the other cliff face to the Northwest and use a Rope Arrow to quickly transverse the gap and let you start moving toward the Beach again.
When you get through the tunnel use a Rope Arrow/Ascender on the wall to the left. Get the XP Cache and then get into the Zipline and use the Ascender to climb up to the platform far above. When she lands there are 3 more Solarii who are standing around. The good news is they are looking the other way. Get the one nearby the camp fire with a Stealth Kill. After that just pick off the other 2 Solarii, who are wearing helmets, to move on. Take a moment after you have dealt with the Solarii to head for the ledge just below where you landed. You will find the Thirteenth GPS Cache of the area. Jump the gap and then go over to the Zipline. Use this to get back down to the beach. From there just head toward the Camp. This will trigger the next cutscene and advance to the next Chapter.
Once the cutscene ties up go back to the camp fire. This will trigger the Seventh Journal Entry from Lara. Take some time also to talk with Jonah, Reyes and Whitman as Sam is asleep. Whitman and Reyes are by Sam close to the fire. Jonah you will find just to the North of the Camp. Talk with him and if you have talked with everyone else you will get the “Chatterbox” Trophy/Achievement. Then you can start for the nearby Tomb, “The Temple of the Handmaiden”. Getting to this tomb is not too hard. It is Northeast of the Camp on the beach. Just look for the Steel Tower poking out at an angle with the Zipline running from it (it is where you landed none too long ago) use the Rope Arrow/Ascender to rip open the doorway and head inside. Just go over to the left and it is a short walk to get started on the Tomb itself.
After you complete the tomb there are still a few things to be found on the Beach but they are found en route to the next location. Head to the Northwest part of the beach where the Marker is. Use a Rope Arrow/Ascender to pry open the door to the elevator. After that you need to approach the lever and use the Climbing Axe on it to try to bring the elevator down. It will come crashing down instead. This means you need to climb on up instead of getting a ride.
Head over to where the Elevator fell and climb onto the lip the area. Scamper up the first 2 parts to reach the beginning of the craggy wall. Once on the wall head over to the left, jump the wiring and catch yourself. After that just climb up and to the left to get to the top of the cliff face. Go over to the left at the top, to the base of the Radio Tower to find a Salvage Crate. After that go over the opposite side of this small plateau, to the Northeastern part of it. You will see some hand holds you can use to get to the top of the old elevator shaft.