Torunn's get ready his weapon, with his maul at the ready to use it after the first volley of his musqueet. 

"Stand on my shoulders and pull that lever." Ilezenya says to Mullo, bracing himself on the column (or wall or whatever the lever is mounted on). (If needed, here's an Athletics check:  13)

Despite her best efforts, Mullo is unable to shift the lever.

Toruun does not have any black powder left and cannot load his musket

"Well, so much for that idea..." Ilezenya mutters. He heads over to the shaft and looks down, trying to see what's coming up on the chain... (300' darkvision)

While everyone is scrambling to try and stop the lift, Beedo immediately took the opportunity to find any crates or bends to navigate around and hide out of sight.

-Beedo's Hide Attempt: 11.

But as for Vark and D.O.R.K, only a timely warning from Devin might spur them to act, as any whispering on the scouting team's part to avoid notice/keep their words from echoing would be loss to them. With or without the warning, she would've still at some point got a torch at least ready in full anticipation of joining the others deeper in the chamber. But with some warning, she'd motion for Vark to join the others closer to the potential frontline, while she herself at the very least would make her way no further than the edge of the natural light coming from outside with a torch in one hand and shield in the other to act the part of bait... on the off chance the rest of the party try to hide elsewhere in the chamber.

Devin, when he realizes that something is going on, decides to have Aslan fly to where the others are so he can see what is going on.  He stays with D and Vark and tells them whats happening as he watches and listens through Aslan. "Something is happening at the shaft, the chains are moving.  Don't know what that means.  The others are trying to pull a lever that is about 10 feet off the ground but they can't get it to budge.  Maybe the lever stops the chains.  If needed, I can activate the Driftglobe for light." 

Through the eyes of Aslan Devin tries to understand the purpose of the chains and the shaft. If needed Devin moves closer to the shaft to allow Aslan to fly down the shaft to see what can be seen.

Investigation 16

Cursing in dwarvish Torunn holds firm his maul and gets ready to the fight. 

"Giants... " he says and spits on the ground.  

As Illezenya makes his way to the edge of the shaft the chain stops moving for about 30 seconds before starting up again. 
 
Illezenya continues to peer down the shaft. The chain stops and starts a further six times before at the edge of his vision Illezenya can see a single large platform approximately 60 feet in diameter approaching. As far as he can tell there are no figures moving on the platform!

Ilezenya relays this information to his companions, standing ready to cast something if needed...perhaps this movement is a predetermined raising and lowering of a lift?

Mullo moves over to the edge of the shaft.

Ebonitus remains with Devin, listening intently around him, as he cannot see much. Hearing Devin's description, he suggests they move toward the pit's NW corner (opposite side to the chain and lever)

"Agreed" Says Devin in response to Ebonitus and helps lead them that direction.  He takes out the driftglobe a gets it ready in case its light is needed.

Hearing that the climbing platform is empty Torunn takes a better look to the chains trying to discern if they are being pulled from below or it is some kind of automated mechanism. 
(Investigation if needed: 4) 

but he cannot tell for the shake of his beard…

Ilezenya keeps his eyes on the platform to discern if anything gets on or off, and if it seems to be stopping at intervals which might indicate an automatic lift system.

The lift platform is obviously on some sort of automatic system stopping every fifty feet or so got about 30 seconds. Eventually it reaches the top of the shaft and …

As Ilezenya sees the shaft continuing to rise and stop, rise and stop, he casts a series of dancing lights and motions for the rest of the party to approach. "It's an automatic lift - and our way down into the mountain. Everyone get ready to board it when it reaches this level."

Barring discovering any creatures on the lift when it arrives, Ilezenya steps onto it with the rest of the party. When everyone is onboard, he leaves only one ball of light to dimly light the platform as they descend.

Mullo furrows her brow, but when the lift reaches the top, she quickly steps onto it. She pulls Helmsplitter into her hands and holds it, ready to defend herself.

Has Haetone been left outside?

Yes. She wouldn't have entered the cave.