Heading back the way he came, he finds that the power has turned on a projector, showing footage of the German expedition. The footage shows the El Dorado statue, along with one of its victims. A man has been chained to it, and is attempting to attack the camera, behaving exactly like the descendants.
On the table beside the projector, Nate finds a letter: the last testament of Francis Drake. In the letter, Francis Drake explained that the treasure bears a "terrible curse," and that it was he who destroyed the Spanish ships in an attempt to stop it from ever leaving the island. Reading this, Nate realizes that the treasure also affected the Spanish hundreds of years ago. Through centuries of inbreeding, they became the descendants that were currently roaming the island.
Pushing on, Nate arrives in the control room across from the one that he left Elena in. He sees her being captured by Roman and Navarro. Roman activates the microphone on his end and speaks to Nate, thanking him for leading them to El Dorado.They then leave, taking Elena with them in order to stop Nate and Sullivan from trying anything "creative."
Navarro's mercenaries, now bearing protective helmets, enter the bunker and try to kill Nate, but they soon get caught up in fighting the descendants. Nate fights through both descendants and mercenaries before climbing a ladder that takes him back up to the monastery above.
The first thing you must do once you enter the generator room is head over to the back of the room and activate the switch. The power will turn on and you will then be confronted by descendants. Head through the door on the left, which just opened, and activate the switch in that room. The room on the other side will open up. Head over there, and pull the switch to unlock the middle door. Run out of there as quickly as possible before the descendants kill you!
Now, you must find a way out of the bunker. Head down the hall, turn left, then right, then right again. Head down the hall, leading into the room with the movie projector. After the cutscene, you will be attacked by more descendants. After taking them out, head up to the door to get it open. Once through, head down the hall, turn right and head down the hall going into the control room.
After the cutscene, you will be fighting through hoards of enemies and descendants. Here, you will find some M4 assault rifles, which are more effective against the descendants than the MP40 submachine guns. Look out for the guy in the control room above, pointing the laser. After fighting through all of those enemies, make you way around to a ladder, and climb yourself up to the next chapter.