Jahn will attack the last crab.  

25 to hit for 5 slashing damage. 

(Incase that's enough ...)

Ulysse points at the crab, "Light it up!" (BA to command wildspirit to attack the crab)

Ulysse throws his flame in his hand at the crab too.

Produce Flame: to hit 23, 6 fire damage 

Wildspirit: Flame Seed - 6 to hit...

The crab survives the blow from Jahn’s battleaxe, and then the potentially deadly produce flame attack seems to be decreased by the water, leaving the crab barely still alive as a flame seed from Ulysse’s Wildfire Spirit wizzes over it. 

Crab(’)s’ turn

The crab takes the disengage action and swims out of Salsvault. 

Combat is now over. 

Also, Jahn and Erzer, make con saves for being in the frigid water at the start of your turns. 

18 Con Save.

With the crabs gone, Jahn will stow their axe and grit their teeth as they attempt to drag this chest out of the wall and onto dry land.  (If this is not possible at all Jahn will attempt to use the keys to open the chest)

"Bring the crabss with ya, we can have ssome legss next time we sset up camp" Ulysse notes as Erzer starts getting out of the water. Ulysse will send the wildspirt to hover over Jahn hoping the flames heat might help as well as planning to firey teleport him back to dry ground when he's done with the chest.

A little bit of saliva dribbles from Sable's mouth and she looks forward to fresh crab for the next meal. That's the best reason yet to say with these people! 

She then wipes the quickly freeing saliva away. 

Con save: dirty 20. At Ulysse's request, Erzer grasps the largest crab corpse in the water and drags it back onto land. 

Quote from Stivali >>

18 Con Save.

 

With the crabs gone, Jahn will stow their axe and grit their teeth as they attempt to drag this chest out of the wall and onto dry land.  (If this is not possible at all Jahn will attempt to use the keys to open the chest)

 The chest is built into the floor, but after trying both keys, the second one unlocks it. Water pools into the chest, which causes a cloud of sand to come out. Once the cloud clears for the most part, see within the chest are 20 gold vials, and an inch diameter orb carved from ivory. 

(20 and 18 both succeed)

[No 50 gp diamond? Ahh man.]

Once Jahn appears to start moving back towards the group, the wildspirit will teleport Jahn out of the water.

Jahn would absolutely take the vials and bring them to dry ground.  They'd absolutely take multiple trips to grab all 20 vials.  Jahn would also attempt to find out if these are the cures they are looking for. 

Making it out of the water, Jahn would bolster themselves.  "Dawnfather thank you..."

Just curious if he also takes the carved ivory orb?

Oh yes, I read that wrong and Jahn would grab the orb too.  

(Do we wish to take time to decipher the vials/ cook meal/ try to find a dryer spot that might warm up and attempt to dry clothes?)

(At this point yeah.  If the vials are our antidotes.  We can just get out of here.  Lol.  Maybe we can destroy the vials of disease while we're here.)

Erzer asks for the orb, examining it to see if it seems magical. It could be a very special orb.

You would remember that Elro said the cure was “a milky liquid the Aeorians stored in gold vials”.

Quote from RippedRhinoVikings >>

Erzer asks for the orb, examining it to see if it seems magical. It could be a very special orb.

 Make an arcana check.