Velmine moves behind the zombie (and stands at Q10) to attack the Wight instead of focusing on any of the weaker undead. She reaches with her rapier and tries to put an end to it.

Attack: 28 Damage: 50 Piercing Damage (Sneak attack because Corvin is in proximity to the enemy.)

Landing the hit or not, Velmine disengages quickly, and moves away from the undead mob (ending at S11).

Eiren takes Velmine's place (Q10), and in his deadly dance, unleashes with magical rapier strikes at the wight (or at either Z3, if the wight is defeated).

Attack: 19 Damage: 8 piercing

Attack: 14 Damage: 10 piercing

Velmine moves around the Zombie and attacks the Wight. Her rapier deals what should have been a lethal wound, but the Wight is still standing. 

Eiren moves to where he can attack both the Zombie (Z3) and Wight. With two quick slashes of his rapier he finishes off the Wight and leaves the Zombie barley undead.

Xavier is up 

Xavier moves to Q11 and casts burning hands at the three remaining zombies dc 16 dex save or take 5 fire damage

Wisdom save 7

Z3 Dex save 12

Z3 Con save 4

Xavier moves to where he can touch the closest Zombie and destroys it with a fiery touch.

With the Dread Warriors and Wights gone Corvin and Baik are up 

Baik stays where he is, as a Bright Light showers Z1, encasing it in energy as he attempts to burn it down.

(DC 16 Dex save, or 14 Damage)
(Radiant damage)

Z1 does not try to evade the spell Baik casts and is destroyed. 

Leaving Z2 to Corvin?

Burning hands is a 15 foot cone, cast forward from where I moved it should have hit all 3 zombies 

Quote from Teechu >>

Burning hands is a 15 foot cone, cast forward from where I moved it should have hit all 3 zombies 

 You're right. I thought it was a Touch spell and didn't look 🙁

Z1 Con save 15

Z1 Wisdom save -1

Z2 Con save 14

Z2 Wisdom save 18

Xavier moves to  - the closest Zombie dies in a fiery blaze. Z1 and Z2 are still standing, and Z2 starts as if stung.

With the Dread Warriors and Wights gone Corvin and Baik are up 

Z1 does not try to evade the spell Baik casts and is destroyed. 

Leaving Z2 to Corvin?

(VanderLegion contacted me a few days ago saying he wasn't feeling well and I could post for him. As his turn is fairly simple, I decided to do so.)

Corvin casts a Sacred Flame at the remaining zombie. The zombie doesn't try to escape the magical flames and takes 14 radiant damage. The zombie is reduced to ashes.

Everyone receives 300 Xp.

Do you want to do anything in this room or leave as fast as you can?

Rellahne what do you do with the Mastiff?

"We should press on, before these lights lure us in and make zombies out of all of us..." Eiren says. He will lead the way east & north through the room, trying to shield his eyes against the lights until he's out of their area of influence. 

Time in the Doomvault: 0 Days 13 Hours 48 Minute

Baik (25/77) - 0/1 Saving Face, 0/2 rages, 2d6/9d6 healing light, 0/1 tomb of levistus, and 1/2 fourth level spells. Hit Dice 5/8 Warlock, 0/1 Barbarian. 

Corvin (66/66) - 1/4 first level spells, 3/3 second level spell, 1/3 third level spells, 0/3 fourth level spells, 0/1 fifth level spells. 0/5 Embodiment of the Law, 0/2 Channel Divinity. Hit Dice 3/9.

Eiren (54/63) - 1/2 Bladesong, 0/1 Second Wind  0/1 Action Surge, 4/4 first level spells, 1/3 second level spells, 0/1 Blessing of the Raven Queen, 1/1 Arcana Recovery. Arrows 30 remaining (out of 40). Hit Dice: 3/7 Fighter, 2/2 Wizard. 

Velmine (44/57) -Martial Adept 0/1. Bag of Tricks 2/3, Hellish Rebuke 0/1, Darkness 0/1. Hit Dice 3/9 - [Animal Hit Points: [Mastiff: 3/3]

Xavier (42/65) -3/4 first level spells, 2/3 second level spells, 3/3 third level spells. 2/3 fourth level spells. 0/1 fifth level spells. 3/9 Sorcery Points, Healing Hands 0/1, Necrotic Shroud 0/1. Hit Dice 6/9.

Quote from Flyingmatthew >>

Rellahne what do you do with the Mastiff?

(Velmine*. Rellahne is in the other game.)

"Fair enough, quick and fast, out of here... I just need to be sure my dog is coming. I didn't get hurt at all while moving to here, here's hoping it has the same luck." Velmine more or less explains and commands the mastiff to just risk itself and move as quickly as it can, eyes closed, hoping it is able to find Velmine based on smell alone.

Mastiff Wisdom Save: 2

The mastiff is transfixed by the magical lights. She takes 12 necrotic damage, and returns to wherever it came from. 

As you approach the northern passageway you can hear the sounds of water rippling from the darkened cavern beyond. As you get to the cavern entrance everyone except for Corvin (who doesn't have Darkvision) can see...

The walls of this cavern are the same dark shade of blue as the pool of water that fills the center of the area. Ripples spread across the surface as if the water has been recently disturbed. Around the cavern, narrow alcoves hold enormous globes of blue liquid suspended in the air.

In the west side of the room is a black gate, and on the wall near it is a contact stone.

The cavern is slimy and wet and is considered difficult terrain.

What do you want to do?

Let's try to avoid the water and check out the west black gate?

Agreed!

"Let's stay clear of the water, until we figure out why it's moving about like that..." Eiren will follow close behind Corvin.

For the best! We don’t know what tricks the water has up it’s sleeve, especially after that last room. Baik speaks, clutching his Spear as he follows alone as well.

Quote from Pertuie >>

Quote from Flyingmatthew >>

Rellahne what do you do with the Mastiff?

(Velmine*. Rellahne is in the other game.)

"Fair enough, quick and fast, out of here... I just need to be sure my dog is coming. I didn't get hurt at all while moving to here, here's hoping it has the same luck." Velmine more or less explains and commands the mastiff to just risk itself and move as quickly as it can, eyes closed, hoping it is able to find Velmine based on smell alone.

Mastiff Wisdom Save: 2

I missed the bold lines above, that was pretty close to how I would have handled this situation myself. 

Between Smelling Velmine and hears her the mastiff is able to navigate through the room, until Velmine let's him know it ok to open it's eyes. 

(I'm not going to redo the map just to put him back in but consider him in L28 right behind you.

(Sorry I haven't posted yet. This room is complicated and I wasn't sure how to proceed.)

Corvin can't see in the dark, so he casts Light on his Warhammer. He agrees with Xavier and Eiren, and the party starts moving towards the Black Gate. When you are about halfway there you hear the sound of water splashing again you hear the sound of a massive something getting out of the water. and a huge tentacled creature climbs out of the body of water and moves to the northern floating ball of water. (Int check 10). Somehow he makes it move towards him until it is encompassing him. He swims around so he is facing south and sees you. Suddenly (1=Eiren, 2=Xavier, 3=Corvin, 4=Velmine, 5=Baik 4) Eiren receives a telepathic communication. "You don't look like the Red Wizards or their cronies. I am very hungry perhaps they won't be angry with me if I eat you!"

Eiren you can respond (see spoiler below) before anyone does anything to either the monster or to the party 

Everyone roll initiatives 

Monster's initiative 3

Corvin's initiative 20