(This is a log of my players run through the Out of the Abyss campaign (After a brief dabble with Harried at Hillsfar first. Spoilers abound, though it’s likely the team won’t play the module in the way you, the writers or sanity intended).
Everything is on fire and Whitey has been nibbled by spiders. Now is not the time to panic.
The plan has gone out of the window and after careful consideration the party decides to go with it.
Aiyu: “Quick! Everyone out the window!”
The other prisoners are have followed the heroes, led by Eldeth, the dwarven woman Aiyu had much a strong impression on earlier.
“This is your plan? Set fire to everything and jump down into the darkness?”
Aiyu: “Well, no but we didn’t really have much of a plan to start with…”
Sargen: “Just go!”
Anastasia had mostly recovered from the poison and was trying to rouse Whitey by slapping him around the face.
Whitey: “I SAID I’M AWAKE!”
Anastasia: “Sorry, I can’t hear you over the sound of the raging inferno. Were you apologising for getting us into this?”
At that point the webs they were standing on gave way and the party plumetting into the waiting depths of a lake below, surrounded by flaming debris.
They soon extricated themselves from the lake and took stock of their situation.
Zook: “Wow! Nice job, Aiyu! When did you realise we were over a pool?”
Aiyu: “Over a pool? I mean, of course we were! Go me!”
Zook: “…”
Sargen: “Is everyone ok?”
Anastasia: “I saved Whitey.”
(They watched as the ranger dragging herself from the pool)
Targen: “Oh thanks awfully.”
Whitey: “Look, I’m sorry for screwing things up with the priestess but in all fairness I was very tired and…. why are you all looking behind me?”
“…”
“There’s something horrible there, isn’t there?”
Yes. Yes there was. Rising out of the pool behind Whitey was a large, amorphous ooze. Having only been feeding on small vermin and the cast-offs from the Drow, the ooze was pretty keen on “cuddle time” with the heroes.

“I think it can hear you Zook.”
After a short but brutal fight (and the inevitable KO of Whitey) the party prevailed. Soon, they were rejoined by the other prisoners they shared a cell with.
Targen: “How did you all get away?”
Eldeth: “We came down the stairs. It seemed easier.”
She had lead the rest of the captives from the cells and now there was a lot of discussion about where to go next. The heroes themselves weren’t natives of the Underdark and so they canvassed the survivors to see what the best way forward was. After a brief discussion, they compared notes.
Zook: “There’s a small settlement nearby run by Shuushar’s people, the Kuo-Toa. We can get a boat on to other places in the Underdark.”
Whitey: “What’s the town called?”
Zook: “Sloobludop.”
Whitey: “Bless you.”
Sargen: “There’s a town of the those cute little mushroom people nearby, like Stool. He’s keen to go there.”
Targen: “How did you understand him?”
Sargen: “I dunno; the air smelled funny then I was seeing pictures from his head.”
Targen: “You’ve been eating those blue mushrooms again, haven’t you?”
Aiyu: “I think Buppido said there’s a big city where we might be able to find a route to the surface. It was hard to tell because he kept cackling to himself and mumbling about ‘making them all pay'”.

Zook: “Eldeth and the other gnomes suggest going to the Deep Gnome’s city. They think there’s a way to the surface there.”
After a bit of heated discussion the team decided to head to Shuushar’s city. While there was plenty of strategic justification for that, the main reason was getting as many people to say “Sloobludop” as many times as they could.
The Underdark is an alien, inhospitable place. Glowing patches of moss, “forests” of tall mushrooms and the fact that all the food they foraged for tended to squeak and wriggle when consumed made the journey unsettling. At one point the party paused to watch an enormous purple worm smashing it’s way through a lower canyon. Strangely, it was covered in what appeared to be glowing fungus.
Before they settled for the night they were ambushed by an enormous swarm of skeletal hands. After a long, protracted period of deadly combat and inappropriate bodily contact they cleared out the critters and settled for the night.
Amongst the detritus Anastasia discovered a cache of potions and decided to keep them secret from the rest of the group. She stealthily slipped them into her backpack while standing in front of the campfire being watched by everyone in the party.
Zook: “What are you doing with those potions?”
Anastasia: “What potions?”
She then proceeded to dramatically twirl her cloak around her face and hid under her bed sheets.
Zook: “We really have no chance of survival down here, do we?”
DM Notes: They had no idea there was a pool underneath them. Luckily there was one referenced a bit further ahead in the module which I re-purposed. Otherwise I'd probably have created one out of whole cloth to spare a wipe. DMing reminds me a bit of when my children were toddlers; you're always trying to counteract their suicidal impulses but no matter how much you child-safe the house / Dungeons and Dragons module there's no way you can think of _everything_....