Adray does a quick inspection of the three doors.  Depending on how they open and close he'll ask the others to block the doors to keep them shut.  If they swing inward he will offer his rope to do.  If they swing outward, then he will offer his spear wedge against the the floor/wall and the door and have Nibs stand over the other.  Turning to Fran he says, "Acid should work and not set off the gas if any has leaked here.  "Polly, you have watch over the hallways." 

When ready he will draw his short sword and open the door.

Dodge action to impose disadvantage if something attacks.

 Just to be clear: you open the third door to the right with the sound behind it?

HUGE CORRECTION! Sorry, had to tell it right away too:

The door at the end of the corridor - there are sounds as well behind it. Unmistakable sounds of a tortured and not yet broken creature: painful grunts and coarse cursing, you can not even tell if the victim is a man or a woman.

Polly nods and take out her quarterstaff. “I have no offencive magic left except for fire bolt, and that might blow us all up..” she swallow.

If only I had take note during the sparring lessons at the academy..  

 Choir stands behind Adray and Ordrag, warhammer raised and ready to battle!

Fran would look to Polly with a nod. She appreciated her speaking up, “I know it’s not ideal, or what you’re trained teh use, but,” The artificer would offer Polly her prized light crossbow and some bolts before Adray would open the doors. “It’s something and a way to keep you out of melee.” She’d give her a quick crash course on how to load it, aim it and what to press to fire it .

Fran would also pull out her healers kit to patch Polly up from the ghost axe attack.

Healing: 5

The artificer will then arm herself with her blades, ready to rush in after Adray, Nibs and Choir.

Whatever happens behind the door, it's unlikely those inside are sitting in the dark, and so far the only light source you saw around was torches. Your noses also tell you, the smell of flammable gas is left behind.

Nibs opens the door and Adray is there, shortsword up ready to lash out at an enemy.

Readied action to attack as soon as the door is opened.

The room behind the door was not big but probably the most horrifying out of all you saw so far. Rusty shackles on the walls, the walls itself and floor of this room are covered with streaks and splashes of dried and fresh blood. Two dangling bodies are shackled to the east and south walls. One is an elderly male human; the other, a young female tiefling. Both are covered in bloody gashes, and neither is moving. In the middle of the room is a sturdy wooden chair with a bloody whip draped over it. A bucket half filled with something white (salt sits?) on the floor nearby.

You finally got your wish - those not shackled did not expect an attack that deep into the tunnels. Did not look overly dangerous either - a half naked man with hands covered with blood, and another one in a robe with a hand full of that "something white" rubbing it into the wounds of the tiefling.

Collective initiative for torturers - 11

Roll Initiative in case Adray leaves something alive in there.

Adray Initiative: 11 + 4

Choir initiative: 20

Polly initiative: 11

Nearly forgot Nib's initiative: 8

As soon as Fran rolls - just go ahead and attack. I think it's a clear case "how do you want to do it?" - those cultists get 2 full rounds on them from the group.

Fran initiative: 5

Just go ahead and attack!

As soon as Ordrag and Adray are not blocking the door, Choir charges in and whacks someone evil with her warhammer! Attack: 9 Damage: 5

Catching them unawares for once, Adray rushes in with a leap through the air trying to come down with the impact of his knees and short sword for a downward thrust.

Shortsword: Attack: 22 Damage: 8

unarmed: Attack: 17 Damage: 5

Nibs rushes in and swipes with his scimitar and then again with his shortsword

Attack: 8 Damage: 4

Attack: 15 Damage: 9

Polly stay in the door opening so she sees what happens but rais the crossbow she got from Fran. 

round one.
Crossbow attack: 18 Damage: Unable to parse dice roll.

if there is a round 2:

crossbow attack: 14 Damage: 11

Torturers blood added a few fresh splashes of red to the walls and floor and few fresh notes to the stench in the room. As a reward, you had two bodies shackled to the wall - a human man, hopelessly dead, and a red skinned tiefling woman, still breathing, practically naked covered in blood dusted with - now you can see it clearly - salt.

Choir still has the keys that unlocked Klim's shackles. She tries freeing the Tiefling, ready to catch the unconscious body as it falls.