Episode 19 of Minimalist takes Team B.S. into a dungeon that is mostly underwater, on Kaladun's complete the monument map. It is full of guardians and charged creepers, and the hard part is breathing. By the end they have swum out with the blue wool, and it goes onto the monument.
Guardians under the floor
The dungeon opens on a stone room with sugar cane, lava and running water. "Watch out for any sand, could be trapped." Then the first guardians show up, and the recording admits "I don't know their properties." The potion they brought is the wrong one: "We don't need fire resistance in here, we need water breathing." There is talk of building an airlock. One of them has Depth Strider on their boots, and the other has Depth Strider plus Aqua Affinity on a helmet. Doors go down to make air pockets. "I have a door, I can breathe."
Charged creepers
The next prismarine room has a spawner for charged creepers. Shouts of "Charge creepers!" go up, and the spawner comes down soon after. One chest gets blown up in the fight. Another holds a Blast Protection book and some lapis.
Line of sight
Further in, there is a zombie spawner, and a reminder that guardians have thorns. A pair of Depth Strider III boots changes hands. Among a stack of potions comes the thing they needed: "There's water breathing. Well, there we go, now we have water breathing."
Then they go down into the deep rooms. Fighting guardians "doesn't really work," so the plan becomes hiding behind walls and doors to break their line of sight, then healing up between runs. The chests down here hold gunpowder, an enchanting book, bottles o' enchanting, and lapis, "lots and lots of lapis." The water breathing runs out partway through. A Respiration helmet turns up in another chest and goes on right away.
Finding the way
For a while nobody can find where to go next. Behind some glass there is only bedrock, and one of them decides "it's got to be down." Circling the middle pillar keeps the guardians from landing hits. Eventually a room of lapis blocks and glowstone turns up with a chest in it, and the chest holds blue wool. "You grab one, I'll grab one, and then we'll get the heck out of here." With "18 seconds on my water breathing," it is a race to the top while the guardians zap them, but both make it out.
Where it ends
Back at the monument, Basket sets the blue wool in its slot next to the purple. The Deaths board never moved this episode: Scoti_Garbidis 15, BasketMC 13. There is a plan for next time too, an area off the potion area, "possibly next intersection."