Pensive creeps along the corridor sending images to Kaylyn of what he sees.  She quickly tells him to send the images to the whole party when the new creatures appear.  Whether he is able in time to share the images is hard to tell. Maybe Kaylyn is too distracted by her other work, maybe he just doesn't do it in time.  Its hard to tell.

DC 12 INT saving throws 12 and 5 

oops, he should have advantage, so that would be the first roll with an advantage roll and here is another rolled properly with advantage

11

I'm not sure what the dice roller is doing.  I show a 12 and a 5 for the first rolls.  But if I hover over the 5 it shows a roll of 1d20+6 with a result of 14.

The next roll only shows 1d20 when I hover over it but the text reads 1d20ad

So here are 2 more advantage rolls if needed to clear things up.

20

16

Sekkar made a step back and gulped, quenching the light of Dawnbringer. Naagar was as close to a friend as a kuo-toa can be a friend to anode denizen of the Underdark, when it's a bit more than "I'll let you live today". To see him like that was ... disturbing even to him. "Naagar," said the ranger mostly to show recognition and stopped Derendil's hand already raised to strike the affected creature. "Friend?" asked the quaggoth in a confused tone. "Friend," answered Sekkar with just a hint of hesitance. He gulped again and explained. "Naagar is... was a hunter of his village. The best. He can not return looking like this, would be exiled even if being ... normal but known to be captured. He is dead to the village."

Sekkar never watched Rhayna's attempts to help someone so intently. "Can you restore him?"

Kirin steps back and tries to record to book what Rhyana is doing to open the chambers as well as what he can see of the machine itself. He never met the fishmen and no interest in the interaction for now. 

Rhayna can see from the quiver in Naagar's body that he is in excruciating pain, probably as a result of the terrible stress his body is under. Who knows how many times he has been revived and experimented on, only to fall unconscious again - it is no wonder he begs for the finality of death. Rhayna knows there is nothing she can do to reverse the horrific mutations, and that as long as they persist Naagar will continue to suffer. Nothing short of powerful magic or divine intervention could save him.

Rhayna can do nothing for his pain, except to permit him to stay unconscious, which this chamber can do indefinitely. Spare the Dying could also keep him unconscious if cast daily. But nothing less than Resurrection can restore his body.

Sekkar peers at the other kuo-toa in the next cylinder. Perhaps... there is something familiar about this one too. And those others in the first room... He didn't see it at first, but could it be that all of these kuo-toa are from Loopdilploop?

Kirin inspects the preservation cylinders... they seem to be built in a manner to be able to detach and move, and probably have some form of independent limited power source...

Kaylyn:

Pax continues to guard the hole, patiently waiting for Kaylyn's pseudodragon to reappear...

writing down his obersvation, "Is there a way to determine how far off we are off our target location?" Before turning back to the machine, "I see. I see. The cylinder are removable and have a power source of kind. Possibility a failsafe. Anyone have some tools to dismantle this? Wait, wait, we dn't have time for that. We were going somewherer right?," 

A deeply concerned look crosses Kaylyn's face when Pensive is stunned and she quickly dismisses the pseudodragon to keep him safe from further harm. 

She rushes over to where Pax guards the hole. 

"Some sort of creature attacked and stunned Pensive.  I have sent him away to keep him from further harm but it is likely the creatures down there know we are here.   There were at least 2 more mind flayers plus some other smaller creatures.  Be on guard."

She then tells the others the same and then returns to stand near Pax.

Pax nods to Kaylyn and takes a step towards the hole and glances down, then steps back, taking up a guard position again.  She casts See Invisibility just in case, taking another quick peak before stepping back once more.  How far down is it?

Glancing back at the others casts message to Sekkar, "Hurry up back there, they know we're here and will likely be coming soon." 

(20' down to the next level)

Sekkar moved along the cylinders. "Nilbool, Oomkaan, Poolidib... That one was not even a hunter." the names came back to him (he never complained about his memory) with sad realization - the illithids did not just catch a hunting party. "They found the village." Usually, it was the matter of time - or speed, who kills who first, but the reminder was painful nevertheless. Underdark owned Sekkar a family twice now. "Step aside, Rhayna." What had to be done - had to be done, and better by someone who knows how. One strike was all Sekkar needed to end Naagar's torture.

Dawnbringer did not object but Derendil was very confused and looked for an explanation. "Broken. Can not be fixed. Can not fight. Wanted to die." The laconic explanation was enough, the quaggoth nodded and looked at other cylinders. The answer was obvious - if they can not be fixed, it's better to end their suffering. The bodies could be placed back inside to keep the appearance if it was needed but with the dead mind flayer on the floor, it might be excessive. Although... "We can pack the monster into the glass thing too."

Once that all was done, Sekkar and Derendil joined the others near the hole. "One rope is enough to get us down". He unpacked his own. "Who goes first?" Since Pensive was there, obviously, they were going after him. Sekkar looked around for something to tie the rope to, but if nothing is in the view, he could help everyone down then jump there himself.

Rhayna was going to protest, but the Cleric knew there was nothing that could have done to help. If anything, the only thing she could have done was to prolong their suffering. She steps back to let Sekkar perform his duties, and she takes out her Journal to record the event and the names of the ones she was not able to save today.

Pax sends a whispering message to Kaylyn, "What did Pensive see down there?  Do we have a safe spot to assemble at the bottom or is it immediately within the enemies view?" 

She sends two quick messages to Sekkar, "Wait, we can't drop into a space if there are enemies there who can attack us. We'd be better off leaving them to come to us. I'm asking Kaylyn what Pensive saw down there before getting into trouble." 

Rhayna looks on sadly as Sekkar puts the suffering kuo-toa out of his misery, and helps to perform the same mercy on the other one without it regaining consciousness. Kirin helps as the three bodies from the common room are dragged into the cylinders along with the dead mind flayer, leaving the place looking quite tidy to any casual observer. Pax feels the familiar sensation as her magic sight activates, but as yet no telltale shimmering auras appear to indicate invisible foes.

Kaylyn promptly conveys what Pensive saw to the others. There is at least 50 feet to the corner where the pseudodragon encountered the creatures. Though they looked small and weak, their mental attack was powerful; plus they seemed to know Pensive was coming, so could also be aware of the rest of the group. Sekkar knows enough about mind flayers to know that these 'intellect devourers' are smart enough not to attack on their own, but will likely remain nearby the two mind flayers. The ranger also knows that if the telepathic intellect devourers are aware of the party, then it is likely the two mind flayers are also, and in the turn the elder brain, and possibly the rest of the mind flayer colony, whoever and wherever they might be... it could be a matter of minutes before the place is flooded with mind flayers... and as yet no exit has been identified...

Kaylyn, having warned the others of what is going on does not wish to be standing in the front line of any attack that may come up from the pipe.  She moves 30 feet down the corridor to the doors that lead to the brain room (south door, west of the hole Pax stands by). 

She then recalls Pensive to appear in front of her and when he does she lifts him up and places him in his spot on her pack.  "Hold on my friend, I'll fix this somehow" 

"Let's be clear. Don't know the exit yet, trapped with undead brain? Our position may be already know. So should we start being more aggressive? Also I'm not stating we should attack yet but merely bring it up as a suggestion" Kirin questions before he remember Sekkar gun ho attitude to attacking first. (is the big brain still undead?)

Pax looks to Kirin, "Agree. We can't wait for them to make the first move. Alright, down we go."  Helping Sekkar with the rope, she tosses it down the hole and sits down on the floor, bracing her feet on either side of the alcove, as she clutches the rope that wraps around her armored back and then she holds, levered around her elbow.  She turns to Sekkar, "Alright, down you guy big guy. Someone watch him, if he gets attacked we'll need to be a LOT more aggressive about our descent...." 

Sekkar watched with a hint of curiosity as Pax took the rope from him and demanded lowering everyone down herself. He shrugged and nodded to Derendil: "Stay here. Help. Get her down, then wait with the rope. If they come here - jump and come to us."

Before sliding down, he fully approved of Kirin's enthusiasm and reminded about the features of the "little monsters" in all their grim glory. "Keep the distance, they don't have eyes but sense you anywhere and eat your brain without a mouth. Strike hard, kill fast - no play with those." With these last parting words, he moved down and quietly moved along the corridor. Stealth was useless in that well-lit place among the monsters that could simply sense your presence. He just hoped to notice them himself fast enough.

Rhayna stands next to the hole, and wait for her turn to be lowered down.

Pensive stares vacantly at Kaylyn, registering her presence but not making any response, and rests beside her shoulder. Sekkar is first down the rope, landing in the dimly-lit corridor beyond. He sees some vague movement at the far end of the corridor, but nothing immediately threatening, so he beckons the others to follow. Kirin and Rhayna are next, and have barely made it down when a loud siren sounds throughout the complex, accompanied by a red flashing that seems to emanate from the walls themselves. Sensing this new urgency, Kaylyn also descends the rope, which Pax then hands to Derendil to hold as he stays on guard.

Sekkar can see two intellect devourers at the far end of the corridor, lurking as if in wait. Unlike many of the denizens of the Underdark, the lizardman can tell that these beings mentally sense his location, despite his usual unnatural stealth...   (in other words, they don't rely on darkvision, so his umbral sight doesn't grant him invisibility against them)

(Anyone with 60' darkvision can also see them at the far end, 55' away. Only two intellect devourers are visible, but Kaylyn reported that Pensive saw four of them, plus two mind flayers.)

Roll Initiative!!

Intellect Devourers act on 14, so if you roll higher then go ahead.

Kirin Initiative: 18

Kirin shouts down the hole, "I know this is a bit niche. Fire in the hole!" Kirin cast Fireball down into the floor below, scuplting it around Sekkar who''s already there

Dex Save: 17

Damage: 28 (If ever there was a time I miss a metamagic ability)