Lets go to the breach first and then deal with stragglers. 

I vote we aim to seal the breach first, so that we can retreat as needed without risking reinforcements.

Jaq nods at both Joe's and Lurn's assessment.   To Joe he quietly adds, "The spider form was a really good idea."

Joe gives a shudder. “Y-yea.  G-great.”

"I like the idea of preventing reinforcements," said Cladmir.  "Does anyone know how many enemies we may be facing?"

"Well, we started with 'at least a dozen,' now that'll be down to 'at least half a dozen.'  And a spider-hybrid one."

Taking the most direct route, the party climb out of the Librarian's level then head to the north stairs up. Spider Ruby scampers ahead of the group and informs Joe the path ahead is clear while Mikram gives directions.

On the forth floor things look largely the same, no changes in layout are visible at least. Well until the party heads east down the main corridor fourty feet. At that point the party see where the wall of the library is instead a gap to a tunnel that is 10' wide and tall and extends into the darkness.

"Huh... think that's how they got in? We going right for it? Cap'n you got a plan, right? Backup is me and this second rate hammer?"

Joe nods abd uses shatter to collaspe the tunnel. (Up to theee times if needed)

Before Joe begins casting Jaq asks, "Aren't we going to head a bit down into the tunnel before collapsing it?  Not right here at the walll, correct?"

As the party started discussing collapsing the tunnel Cladmir quietly reflected that in all his years of soldiering, fighting in a deep dark tunnel was not something that he has experienced before, and certainly not in combination of a spider-hybrid whatever.  Feeling a little nervous he couldn't help but asked, "I'm not well versed fighting in caves and tunnel, and no disrespect to the Cap'n here, but we're in no risk of the tunnel collapsing on us, right?"  And suppressing at the thought of the next question he added, "also -- could those spider-hybrid thing walk on walls and ceiling?"

From Lurn's back Mikram inspects the tunnel and in dwarven comments,

"Ye understand that these tunnels were made to not collapse, right? No pointed earred spider lovers carved these paths."

He has a tone that is proud while also being impressively condescending.

((How far down the tunnel are you going to go and what are you targeting? Just the ceiling there? Let me know that and you can roll the damage for those spells.

@Cladmir, roll a history check please))

“Aye at tha tunnel.  Ye guys may wanna go back a ways befer Ah start.

lurn, take care o ruby if this gets me.”

after they get back she uses shatter as far as she can from herself on the tunnel.

((Lurn leaving his shield with Joe?  Else as far as she can see isn't much. Or have you lit torches?

Go ahead and roll damage for the shatters.))

Cladmir immediately recognized the condescending dwarven tone and bit back a retort as it would be foolish to get in a row with Mikram while stuck in a tunnel.  Still struggling with a persistent, albeit no longer severe, headache he tried to reach back into his memory for any useful information that may keep him alive.

History roll:  20

Cladmir also resolved to be far, although not disrespectfully far, from where ever the attempt to bring down the ceiling was going to be.  At the same time he would also scan the area for any possible signs of threat, enemies, or anything useful.

Perception roll:  9

Left wall and celing (it’s 10’ rad sphere )  9 

Right wall and celing   12 
celing 8 

I'mma interrupt the shatters too. 

"Mikram's pointed out that the tunnel is built to not collapse.  Give us some time."  To Mikram, "The tunnel is certain to be strong, but surely the wise dwarves have put in place measures to ensure their foes can't use such constructions?  Are there any vulnerabilities, or failsafes to ensure it's possible to collapse the tunnel?"

((@Dead, I'm going to say that Lurn stopped Joe before she went to do her collapse plan. Would Joe still have gone ahead and tried?))

Mikram's is quiet before he responds slowly (in Dwarven),

"Maybe... Hmm. Aye wasn't one of those that carved this tunnel. We don't build in weakness," he scoffs. "We sometimes leave existing ones in to use if needed. Aye don't see anything apparent here from the breach but maybe further in?"

No she’ll wait and look for vulnerabilities. Investz 18 

"Let's head in, then.  Hopefully we can find something."