[1] The Lower Road

There's a lot of information here for those looking for it, more than Laaesh might expect, even.

Firstly, when you look closely at the valves, you can see that the nearer one was opened and lodged open with force that is probably beyond what a mere human could do. There's fingermarks in the valve. Not fingerprints, mind, but the actual indentations from someone's fingers as they squeezed the brass while they turned it. You might be able to get it closed, but it'll be difficult. Maybe two or three of you together?

Secondly, you can see several trails of troglodyte tracks here. The first one leads out into the middle of the room and stops dead there. After that there's just a smear that leads away from the tracks. Maybe that trog was dragged away. There's more tracks near the edge of the wall, though, and along that wall, there's acid damage as if the acid were splashed back at the wall. Perhaps the troglodytes built something that protected them from the acid, or perhaps they held something up to guard against the acid jets and it splashed it back against the wall.

However, one last set of tracks is more interesting, because there is acid scoring all around the footprints, but the footprints never stagger, never falter, almost as if the creature were immune to the acid altogether.

Looking away from the troglodyte tracks, you also see a small gutter that runs along the base of the wall opposite the acid jets. Upon closer examination, the floor also appears to be slightly off-level in the direction of the drain. This probably explains why the acid isn't simple standing on the floor and wearing it away. And half a thought strikes you. How much acid can really be left in those pipes, anyway?

That is an intriguing idea. The web wouldn't hold the acid for long, but it might get one person through. I think that can work. I'll let you go ahead and play that out and send someone through if you want to. if nothing else they'd have a shot at that easier valve on the other side.

Verin eventually finds a long heavy piece of iron sheeting. It should withstand the acid for long enough... should. But it's so old it's hard to know for sure. There's only one way to find out for sure.

The webs hold long enough that only the very end of the metal square is hit at all, and even then, it's not with enough acid to really do anything. On the other side of the acid showers, Verin is able to get a closer look at the valve on that side. It is very free from rust, unlike the one on this side, and while at first that seems like a good thing, Verin quickly realizes it is not. The lack of rust is one of the signs of acid washing, and is, in fact, something they learned about in her General Research (aka Dungeon-Diving) course. Using the metal sheeting as a shield, she's able to turn the valve enough to cut off the supply of acid to the hallway, and then leap back just in time to avoid getting sprayed by the loose seal on the valve.

Everyone else should be able to come through now, as long as they don't get too close to the still spraying valve pipe.Beyond the acid, there's a wooden door that stands partially open, probably because a child could push it in even if it was locked, and beyond it, a large room, probably thirty or forty feet wide and almost square, but not... quite. You're not sure if it's the angles or if one way is just a bit longer than the other. Either way, it bothers you. There are two doors here, one leading straight on and one heading off to the north. There are also five levers positioned seemingly at random around the room. We'll call them east, southeast, southwest, northwest, and north. There are no handles on these doors, so whoever designed this was clearly - at least in their mind - trying to be security-conscious. There's no indication on which hallway is the correct one.

Behind the walls, gears grind into motion, the sound moves slowly, invisibly, traceable only by the dust that shakes off of the ceiling as it follows the sound until it reaches the north door, where a wheel turns until a spring-loaded lock shoots out and binds the wheel in place. Now that your attention is on the doors, you can see that each of them has three locks. Two more levers will open the north door. Three of them will open the east door. There are only five levers, so one of them must operate both doors.

This time, the lever and its invisible moving parts lead to the east door, where a lock snaps open.