Katerielle double moves up to the drow then around it staying in melee contact to the partially hidden corridor in L-M 5-6, blocking its escape.

Elila will Dash in Katerielle's wake trying to keep up with her.

Katerielle uses her large beast shape form to circle around the drow and block the passage it seemed to be fleeing towards.  Elila follows Katerielle to do the same, circling around the drow.

The Drow growls at Katerielle, blocking its path and swings fists twice at her...

Slam Attack: 18 Damage: 10

Slam Attack: 15 Damage: 8

... deftly striking the giant lizard twice.

(Everyone's turn)

The drows first blow strikes Katerielle lizard in the head forcing her to revert to her normal elven form. The follow up strike to her torso breaks something and Katerielle collapses on the ground unconscious. 

(( at 0 hitpoints.))

Kit tries to step in and finish the drow off. Attack: 19 Damage: 11 

SneakAtk: 6

Elila also moves in to finish off the Drow.

Stab! Attack: 18 Damage: 7

Leek will move the moonbeam to touch the drow (I can't see the drow on the map...)

And attack with his sling: Attack: 7 Damage: 5

As Katerielle falls limp to the floor, the remainder of the party strike at the drow with increased fervor, landing many solid blows.  The drow looks haggard and tipsy, barely able to stand, as Leek's moonbeam moves to encompass it.

(Rindelk's turn)

Hurl the sphere into the drow! 9

Firebolt that sonava! Attack: 5 Damage: 1

(The sphere can only move 30 feet per bonus action.  Moved closer, but no further effect.)

Rindelk fires a firebolt at the drow, but misses, although the moonbeam burns the drow as if it was hit by fire.  As the drow falls to the ground, its shape changes to an androgynous blue creature.

(XP: 260 each)

The cavern falls silent save for the splashing of the stream falling into the fissure.  Katerielle lies on the floor, bleeding.

(Out of initiative order.  Post at will.)

Elila does what she can to stop the bleeding.

OOC: I don't have Medicine Skill so I'm not sure what to do and I also don't want to make her condition worse.

(See Death Saving Throws)

(It's a DC 10 Medicine check to stabilize a dying creature.  There doesn't appear to be any penalties for failing.  But I would rule this is a group check, so 2 max, or 1 with Advantage.)

Katerielle  death saving throw. 18

Elila does the best she can 13

Leek will heal Kat :Second level cure wounds:  8

With Katerielle stabilized and conscious from Leek's healing, your party takes stock of the situation.

Katerielle gets up shakily. She speaks up," What do we want to do now? Search the bodies? Check out what's down the ropes? See where it was running? Search the rest of the facility?"

Elila searches the bodies for anything useful.

The three bugbears have shields, javelins and morningstars.  The androgynous blue creature is naked and carries nothing.

Elila pokes the blue creature with her sword to make sure it's dead.

She also grabs 5 javelins as she thinks they might come in handy.