(Boona is welcome to make a Strength (Athletics) check to try to wrench or smash open the door.
Jurgen is welcome to make an Arcana check to sense whether the magic aura he and Ruven sense has any direction to it.)

Boona steps back and shoulder barges the door.

Athletics- 11

( FFS)

Wham! Boona finds the double door – made of 6-inch-thick cut slabs of stone fitted with iron handles and hinges – is impossible to smash in. The hinges are melted – it's not budging.

But something does. Bryony sees a flicker of eerie blue light through the cracks. A hissing voice emerges from within that sends chills down your spines...“Who dares pry at my domain? Begone or join my legion of the dead! ...Pathetic grave robbers, you scratch at the scraps of my legacy like rats. I was a mage of unparalleled skill; you are but fumbling children. Leave now, and perhaps I shall spare you a fate worse than death.”

" Boona pry!", she replied confused.

" Sorry?"

Then she got quiet as she tried to work out what was worse than death.....she stayed that way for a while.....

Jurgen, just as he is about to turn on his Arcane mind, the voice booms out; startling him.

"Hello there. My name is Jurgen, friend of Gundren Rockseeker. He had come to this mine but was attacked. We are searching for his killers. I respect you great mage, I am an Artificer, combining science, technology and magic. Do you know if there was any others here recently."

(Jurgen: Make a Deception check.)

Bryony steps back a few paces, startled by the voice. The charge of grave robbing makes her feel guilty, as she was thinking of what was in that chest.

"I'm sorry," she stammers. "We're just looking for the people who hurt our friend."

A translucent, skull-like face emerges through the stone door, flickering with unearthly blue light. The temperature in the cavern drops.

“Your lies drip like rancid oil from your tongues," rasps its hissing voice. "You speak of wounded friends, of seeking killers—I hear only the dull clank of greedy fools ready to steal from my treasury. Do you take me for a witless shade, that I should guide you through my domain? Look around, little Artificer—see the broken husks I command. They, too, once claimed they had come for some ‘noble cause.’ They, too, bent their knees, pleaded for mercy, and promised to leave my riches untouched. They rotted swiftly… and now they rise at my bidding. You cannot fool Mormesk. I have heard every form of groveling. I have no mercy to give. Your hearts beat; your breaths cloud the air. That vitality… it mocks me. Shall I allow you to roam free, parading your life before me like a banner of insolence? Come forward then—offer up your mortal spark. For this is my realm, and I claim your pathetic souls!”

It reaches out with a semi-transparent, skeletal hand through the solid stone door to grab Bryony.

Roll initiative!
Mormesk: 13

Jurgen Init 13

Initiative: 17

Bryony yells, reacting to the skeletal hand grabbing onto her. It feels cold and utterly repulsive.

Initiative: 22

Quinn drops his torch grabs Bryony with his free hand. He pulls her away and backs up away from the door. 

Initiative:
   Quinn 22
   Bryony 17
   Jurgen 13
   Mormesk 13
   Boona __
   Ruven __

Mormesk, mostly hidden behind the stone of the door, is currently at 3/4 cover. But anyone with initiative 13 or higher may act!

(Does everyone's position look correct?)

Quinn will pull Bryony back to the north of the pillar, unless she resists, as his action. (Is that correct?)

Boona and Ruven should roll initiative.

Ruven init: 16

Boona Initiative- 19

Anyone with initiative 13 or higher may act before Mormesk!

Jurgen steps up to Mormesk with Draco. "See." Point to Draco. "This is my creation, as an Artificer. Please. I want to learn from you and WE do want to bring the culprit to justice. We mean you no harm."

Ruven, seeing the apparition coming through the door, begins quietly preparing to shoot a few magic missiles at it. He holds back on completing the spell, only releasing it if Jurgen's posturing doesn't work. Not holding out a lot of hope, he prepares to fire at the first sign of violence.

Bryony is pulled back by Quinn, out of Mormesk's grasp thankfully. She nods her thanks at her friend and then turns back to face the skeletal apparition. She pulls out her shortbow and holds it at the ready, prepared to fire an arrow if Mormesk attacks Jurgen.

Action: Hold Action - Shoot arrow at Mormesk if it attacks. 

Bryony pulled away by Quinn, Mormesk reaches instead for Jurgen. "I don't want your little machines, kobold. I want you to join me."

Its ghostly hand reaches for Jurgen.
Life Drain Attack: 22. Hit: 19 necrotic damage and Jurgen should roll a Constitution saving throw. 

Bryony and Ruven may make their readied attacks if they wish.

Then, it pulls back into the door again, vanishing.