Sea of Japan. Syd and Vaughn hop out of a helicopter and use those motorized underwater scooters to propel themselves into the depths of the ocean. Back at the Oops Center, Marshall and Dixon give them directions. Through some crappy CGI, Syd and Vaughn swim into an underwater cave. Dude, that looked like an episode of Aquaman. Bad. Marshall tells Dixon that the agents will be out of radio contact until they resurface. Well, isn't that convenient.
Syd and Vaughn surface inside the cave and strip off their dive gear. They walk over to a monument with three shining squares embedded in it. Syd comments that it's probably been fortified by Rambaldi's followers over the year to prevent anyone from finding the artifacts. Vaughn says that the followers will have to do a better job next time. Man, that was some bad dialogue.
At the Oops Center, Dixon notices an unidentified blip on the radar screen. Marshall scrambles to figure it out, and says that it's a helicopter with four divers. Dixon tries to warn Syd and Vaughn. Did he not just hear Marshall say that they were out of radio contact? Hello? How did he get to be director anyway?
Vaughn and Syd are busy grabbing the keys. Vaughn tells Syd that the keys don't have to ever see the surface. She doesn't understand, and Vaughn explains that the contents of the Rambaldi box are supposed to be a danger to Syd, so maybe they should just destroy the keys. Syd gazes at Vaughn lovingly and thanks him for saying that. Before she can elaborate, Bomani shows up and orders them to put their weapons down. And he's got goons! And they're armed! Syd and Vaughn drop their guns. Bomani thanks them for leading him to the keys, and then tells Syd that she looks like her mother, and he's sure Irina would be pleased to know he got the keys from her daughter. Syd looks pissed, but holds her tongue. Bomani continues, "After all, the Passenger is Irina's legacy." Syd looks shocked, but remains silent. Bomani orders her to bring him the bag containing the keys, and pulls out a giant machete to show that he's not fooling around.
Syd starts walking over, and Vaughn ducks aside and shoots an oxygen tank, which explodes, taking out a goon. Bomani swings the machete at Syd, but she manages to step aside. Vaughn holds off the other goons with covering gunfire. Syd manages to knock Bomani down with a kick, which gives her time to take cover. Bomani gets up, grabs the bag, and runs out. Vaughn takes out another goon, and apparently the third goon went missing, because Syd and Vaughn struggle back into their dive gear and prepare to follow Bomani, who has the keys. Syd realizes that their air hose has been cut, and asks Vaughn how long he can hold his breath. Vaughn says they'd never make it out of the tunnel. Vaughn suggests that they make like MacGyver and use found objects. Syd finds a full oxygen tank, and Vaughn says they can use it to propel themselves to the surface. Syd grabs Vaughn, and they rocket on out of there in some more bad CGI.