"Do we want to go more through that hallway that we just secured, or do we want to go back to the other thing that had four ways to go?" They keep going and try to wrap this part up. "This is the high ground, my friend."
A trap room
The next room is a trap. There's a tripwire hook across the path they would have taken if they'd come in on the right side, and dispensers in the walls. Nobody has a water bucket, or even an empty bucket. One of them bridges across. A little later: "Oh, I set off the trap!" "You did."
One of them has dynamic lights turned on through OptiFine, so a held torch lights things up. That makes it easy to look inside the walls, and it feels a bit like cheating. "I feel bad."
A charged creeper somewhere
There's a charged creeper loose, and they want its spawner gone and the area lit before another one shows up. The first spawner that goes down turns out to be a regular creeper spawner. The charged one is probably in one of the boxes, "probably over my head or something. Or up a level." There's a ghast down the hallway too.
A better shield
On a floor above the same room there's a creeper spawner on the left, a dead end, and a chest with a shield in it. It has Unbreaking III. "I don't know if that makes it any better than what you've got." Later they compare knockback resistance on their shields, and both say 11.11. One of them takes out a ghast spawner, then drops down into a room full of blazes.
Combat Supplies
"Holy cow. What an array of things." On Basket's screen it's a chest named Combat Supplies, with diamond boots and a pickaxe in it among everything else. They split it up, iron gets counted out for the anvil, and one of them ends up with fewer books.
Thick walls
From here the plan is to go up, because "that's what we actually want to go to. It always is." One of them climbs into a crow's nest to shoot across, and a charged creeper falls on cue. The floor in one room is all obsidian, which seems promising.
The walls are the real help. "These walls are awful thick. Thank you renderXR." They dig through them instead of walking through rooms. Through a gap there's a room packed with spawners and an evoker, and nobody wants to go in. One of them gets into a redstone room under it and starts breaking spawners from below: three, then five. A pickaxe breaks along the way. "All spawners down." "I don't think all the spawners are down, my friend." There are more: an evoker spawner inside obsidian, and six others in a cage that might have been witches.
Still climbing
They keep heading up, hoping it's the right way. A charged creeper trap goes off, blazes show up, mobs start fighting each other, and the arrows are almost gone. "This has gotta turn eventually, right?" That's where it stops.