Attack: 10 Damage: 12 Ash will blast once more on his turn. 

"These are tough." 

Darksniffer will stow his bow and draw his sword instead, "Time to skewer fish-man."

(Rapier: 10 for 8 damage plus 3 sneak attack)

The remaining merrow rakes at Og once more with its claws (10 for 7 slashing damage) and snaps its jaws at him (22 for 6 piercing damage -- don't forget Rage damage resistance).

The water is pooling up around your ankles now.

Lophii swims down too the shut-off valve, inserts the key, and attempts to turn off the water.

Strength check I suppose?  4   (facepalm)

"Enough of this..." Yurk bangs his spear against his shield once again, casting Toll the Dead on the remaining merrow for 1 necrotic damage on failed save (WIS DC13)

"OG! NOT! CHEW! TOY!" Swinging the greataxe up into its chest Attack: 12 Damage: 9

Darksniffer draws his dagger (bonus action) and takes another stab at the merrow with his sword (Rapier: 19 for 9, plus 6 sneak attack damage)

The last merrow splashes into the rising water on the floor, and green tendrils of blood stain the water around the corpse.

But the water doesn't rise for long — there's a loud shifting of a mechanism somewhere inside the walls, and the water begins to drain.

Underwater, Lophii's limbs feel cold and faded to him as the adrenaline from the fight pushes him on. With no time to take off his armor before jumping into the water, he's sinking slowly and surely. But he can make it to the valve, and the mechanism turns easily. Soon he can hear the drains open and the water start to rush out, but wherever the drains are, he can't see them and for the moment at least, there seems to be little danger that he'll be swept away somewhere by the draining water.

Back above, as soon as its level drops below the hole in the floor, leaving puddles and the dead merrow, there's another loud shifting sound, and the doors on either end of the corridor swing open. It hasn't been long, but it seems like Lophii would have tried to swim back up before the water. Sorting through the chaos of the skirmish, you realize that he jumped in wearing his chainmail.

(Take 600 XP for getting through the biggest dangers of the trap room. Lophii, being amphibious, is in no danger of drowning, but he'll either need help to get back up somehow, or he'll have to leave his armor (not recommended, of course), or  something else. The water level is dropping slowly now. It's just a couple feet below the hole right now.)

Actually having an intelligent thought Og reaches into his pack and pulls out his rope. ****** part of it around his waist and tying in, he drops the other end in the water. "Use this to climb out."

The end of the hemp rope floats on the surface, where Lophii is nowhere to be seen.

Yurk leaves his shield and weapon, ties the rope around his waste and dive in looking for Lophii.

Investigation: 10

After a moment of searching, Yurk spots Lophii, conscious and alert but struggling in the silt at the bottom of the chamber. 

Darksniffer waits impatiently by the exit, tapping his foot in a puddle to emphasize his annoyance, "Fishman and Turtleman be fine. They know water."

Lophii works his way out of the with the assistance of Yurk. "Thank you," he offers with a bit of embarrassment. "Didn't think that one through all the way.

Athletics: 18 to assist Lophii in escaping his predicament.

With a boost from Yurk, he and Lophii make it to the water's surface. It's stopped draining about 20 feet below the hole in the room above. 

It's a simple but strenuous task to pull first the wet triton and then the massive tortle up from the water with the rope. After a few minutes, everyone is safe on dry ground and the corridor's entrance and exit are open.

Wess peeks in through the entrance. "Guess I'm going to need to order more moat monsters!"

"We go see queen now?" Og puts the rope back in his pack. and walks out the other door. "Lets go Tomp."

"Yes. Let's go see that queen of his. She must be powerful to have so much resources. Let's be careful."

Ash waits for the others before moving. 

"Let's present a united front.  Who will speak for us ?"

To Wess, Lophii asks, "So are we to continue that way to the queen," pointing towards the exit door.

"I have a suspicion that this test may not be over yet." Yurk replies, "Let's continue and see what we find."

Yurk picks up his shield and sword and walks to the far door, looking through before entering.

Perception: 4