The episode opens underwater, at a chest that might be trapped. "I think we're okay." On three, it opens. "Ooh, notch apple." The counter reads Scoti 78, Basket 73.
Back through the trees
Getting back up is messier than getting down. "Ooh, a witch got me!" Invisible Predators are still around, so the way out runs along the dirt platforms they put down earlier. "Me and you and you and me, we're placing dirt blocks for safety." They check the corners of the treetop room, find nothing new, and head back to base. The sorting rule stays the same: "The junk goes upstairs. Good stuff downstairs."
The painting
On the way, a painting in the hall gets a second look. "Now this could be a trick." It isn't one, but it gets them thinking they skipped part of this area. "We obviously missed it because we weren't down where it mattered."
The part they missed is not empty. They take out a Predator spawner, then a charged creeper spawner, while the laser-eyed beacon guys keep stepping out of the walls. "Thank you for coming in here, beacon guy." Another painting comes down, and once the room is quiet there's a chest, and it's full of diving gear.
"Reinforced Amphibian Boots" with Depth Strider II, and an "Advanced Diving Helmet" with Respiration II and Aqua Affinity I. "At least we have two helmets. We only have one of the boots." One of them would rather keep their current boots, so the other takes the Depth Strider pair.
Down the garbage chute
Then it's "into this garbage chute," and the next room is underwater. Charged creepers spawn and shoot upward, and the water is full of guardians. "Oh, and guardians. That's a problem." Bows barely work down here, and there's only one invisibility potion between them. "I've never assaulted a guardian temple, so I don't even know what's the best approach."
The method they settle on is slow: dig a safe hole, swim out, take out one spawner, swim back and heal. One of them gets down to three and a half hearts before getting out. "Quit just swimming in there and getting killed, man." There are sponges in the walls, and some "sponge trees" in the middle of the room.
Two emeralds
Bit by bit they find two emeralds. One goes into the chest in the room where the diving gear turned up. The second makes it back too, at the cost of "one drowning point." Nobody dies this time.
They also talk about Shadow Keys and think they "might have them all from this level already." They remember a book from before the water room: the crystal is "in the aquarium," so that's the job for next time. One last idea: "We should get potatoes and we can kill those guardians. We'll have fish and chips."
The counter ends at Scoti 78, Basket 73. The monument isn't shown, so the emerald blocks stay at 8 of 12.