It takes more effort that you like to admit to pull yourselves out of the 'muck' while climbing the submerdged grate. You imagine that it must be akin to escaping quicksand, and it's somewhat disheartening to have to 'dive back in' on the other side. to the grate's credit, the fluid on this side is much thinner, although there is a bit of a current. the pipe/tunnel is aproxametly 6' accrost. (also, 6' high) you can almost stand, if not for the current pulling you downward, and the slipperyness of the footing (it's very, very slick) there are 'ribs' to the tunnel, and if you are over 6' tall you can reach bouth sides and sort of brace yourself aghinst the current. (strength 3 test) if you are under 6' tall, you can acheve the same effect by putting your feet on one side, and your hands on the other... however, it'll be quite difficult, and require an athletics 4 test to pull it off.
you'd guess that the first 10' or so of pipe leading back would be visable from the entry way (where the people following you are coming from) that's also about as far as light from the night sky penetrates the tunnel... after that... it's very... very dark.
-RuskiFace the Pirate