Roark yells "same to you" at the cursing female voices, then "sic 'em" at his giant spider.
"Any summoned creatures should serve as our advance force, with the company trailing behind." he says.
Roark, Elven Druid

"I knew we should have shot the damn thing."

"Og'rialt!! If you're still out there... DUCK!!"

I shoot an arrow at the portal.

59 - Cicatrix - Southern side tunnel, turn 7

?? I appear to have disappeared. I was behind the main group, weapon readied for battle in case the ghouls got through, and now I'm nowhere to be seen. Is this an amazingly good stealth check or an oversight?

You didn't post any new actions after turn 6, so probably your character remained hidden while answering the call of nature or something like that...
Afaik, our group wasn't yet aware of your presence.

As the Mage remains silent, staring in awe at the vortex, Beldarion considers his options...
-His experience tells him Og'rialt was an expendable party member, and unknown magical forces are better left alone, not to be messed with, but... *rolls dice*
-"What is happening to you, Beldarion? You can't be seriously considering that. Something in this dungeon has changed you..."
-"I just... must try it. If I can't save the dwarven charlatan, at least I'll recover the potions and emeralds he is carrying..."
-"I can't believe I'm doing this. What a foolish way to die."

Beldarion puts a hand on Aslain's shoulder: "Save your arrows. You'll have the chance to shoot Og'rialt when I bring him back"
Beldarion holds his breath, prepares for anything (excepting disintegration or polimorphing, that goes against his own atomic structure...) and jumps into the Vortex.

Thras - Dwavern Mage: I cast magic shield on myself, then I send my Bugbear through the just opened portcullis and follow through too, together with the group.

I actually wrote I was going to take advantage of the Magic Shield only if I was opening the portcullis alone, so I'm surprised I got it. Doc, is it possible to cancel the Magic Shield and give it back to svartalf?

What kind of creatures await us further up the tunnel ? I'm agree with Roark, summoned creatures should be used as scouts !

22 - Kip - Halfling Brigand - Southern side tunnel

Kip examines the end of the rope which was tied around Og'rialt: is it frayed, cut, or burned? Or is it still tied but simply empty of Og'rialt?

To Aslain and Dunward: "Our party is now but three. Shall we follow in hopes of rejoining our companions, or continue on our own? And if we don't enter, how long should we wait for them to return?"

If either Aslain or Dunward choose not to enter the Vortex, neither will Kip. However, he will wait for the moment and see if anyone returns.

If both Aslain and Dunward choose to enter the vortex, Kip will follow.

After Beldarion's talk, I shoot three arrows at the portal.

I look at Beldarion:

"If there's anything waiting for us on the other side, I rather them being injured. After you."

Oh, I'm a bit mixed now. But whatever, I still have my Globe of Protection (and anyone who wants to be under its safety with me is welcome).

I also summon another Holy Guardian, send it ahead with the bugbear, and move forward myself.

Dunward, Human Mage:
"Is there a better death for a Mage than becoming one with the Magic?" Dunward whispered to himself.

"I will follow those two and I do not wish to encourage you to follow us Kip, is it might be a deadly trap, if you will stay I wish you both best luck in besting this cursed dungeon! Fare you well my friends!"

Dunward, makse few steps to gain momentum and casts Levitate on himself and hovers into the Vortex.
"One more thing Master Aslain, Please do not shoot me in the back!".