Sarith: will use 15' of movement to get to H9, use his Bonus Action to move the Dancing Lights (keep quaggoths illuminated, Topsy & Turvey in shadow), his Action to shoot the only quaggoth within normal range (M9), then use his remaining movement to return to his original spot (F10)

Crossbow Attack: 6 Damage: 4

Ront: based on post 516, he moves to H9, throws a javelin at the M9 quaggoth, then returns to his original F9 spot. (Ranged attacks use DEX, so I adjusted his modifiers from his stat sheet.)

Javelin Attack: 17 Damage: 7

Beegred: slips under the quaggoth to get to N8, which makes more room for Jimjar. Bonus action to cast Hunter's Mark on the M9 quaggoth, then action to swing his shortsword at it.

Shortsword Attack: 13 Damage: 5 (that damage total includes Hunter's Mark)

Eldeth steps into the doorway, widens her stance, and focuses her aim on the nearest quaggoth (M9). She smoothly fires two arrows in rapid succession...

• Longbow attack 1: 17 | Piercing damage: 7
• Longbow attack 2: 5 | Piercing damage: 4

She then steps aside, leaving the doorway open for the next ranged attack.

Jimjar rears back with his war pick and makes an upward swing at that same quaggoth...

• War pick attack: 12 | Piercing damage: 8

As soon as Eldeth vacates the doorway, Tozer charges forward and heaves a javelin as well...

• Ranged javelin attack: 12 | Piercing damage: 5

(The quaggoth at M9 is Tozer's target unless, of course, it is fallen, in which case he will aim for the other one)

Buppido raises his hooked spear at the quaggoth directly in front of him (N9) and swings with all his derro might...

Hooked spear attack: 20 If successful, piercing damage: 2

Suffering from a barrage of ranged attacks, the quaggoth succumbs as it gets flung around by the impacts.  Tozer's javelin, aimed at the second quaggoth misses.

(M9 is dead.  I took the liberty of moving Jimjar to M10 to make room on the bridge.  Let me know if that is not OK.  Derendil is left to act before the other quaggoth.)

(Posting may be erratic next couple days.  Don't have access to the best PC's.)

(Sorry, busy weekend, and probably a busy week this week - took the week off from work, which actually makes me LESS able to keep up, so might be less reliable posting.)

If he has the movement speed to make it, Derendil charges across to M9 to take the spot left by the fallen quaggoth.  (I believe that requires a dash, so no attack at the end).  Otherwise, he'll position himself by the door to bet across when he has the chance.

Derendil dashes across the bridge and stands next to the remaining quaggoth (M9).

The quaggoth, surrounded by its ally's bodies and alone, forgets its orders and begins to lash out...

@ Buppido: claw attack: 9, damage 7

@ Jimjar: claw attack: 16, damage 7

The quaggoth will then move into the prison cell, into a corner (R15) with its back to the wall to defend itself.

(attacks of opportunity from Beegred, Jimjar, Buppido and Derendil)

(Narstin, Ferriman, Xilyrah and Valthana's turn)

Beegred bravely slashing the running-away quaggoth in the back: Attack: 23 Damage: 5

Jimjar leaps over the slain quaggoth and brings his war pick in a downward arc upon the fleeing quaggoth...

• War pick attack: 18 | Piercing damage: 5

...and he narrowly misses striking himself in the foot. 

Buppido winces as the quaggoth he pierced lashes out and rips open his shoulder. Bleeding profusely, yet undeterred, he returns the favor to the fleeing beast:

Hooked spear attack: 7 If successful, pierce damage: 6

Xilyrah sees the first quaggoth go down and focuses her Eldritch Blast on the fleeing quaggoth:

Eldritch Blast: 7 If successful, force damage: 8

Derendil AoO 

Attack: 23 Damage: 8

Narstin casts another sacred flame at the creature   Dc13 dex or 7

The quaggoth is struck twice as it flees into the prison cell.  Xilyrah attempts to blast it with an Eldritch Blast and misses.  Narstin casts Sacred Flame and...

Dex saving throw vs. DC 13: 11

... and is scorched by the divine flame.

Valthana, with no good angle on the quaggoth, dashes across the bridge (M11).

Ferriman also dashes across the bridge (L10).

(Eldeth, Derendil, Sarith, Ront, Beegred, Jimjar Buppido and Tozer can act.)

(Sorry, no map until I get home.  The quaggoth is in a nook, inside the prison cell.  It would take a full movement for just about anyone to get into melee with it.  And a good angle for a ranged attack would also require entering the cell.)

Sarith: Does not see any good targets for his crossbow. Uses his Action to recast Dancing Lights, with the same placement (keep Topsy & Turvy in shadows, illuminate quaggoths). Stays in guard tower, for now.

Ront: With no quaggoths on the ledge outside the cell, will Dash across the bridge (if no one is on it), to whatever space seems safe (making space for anyone behind to use the bridge).

Beegred: Will move 10' into the cell to get a crossbow shot at the quaggoth, then move back to his original space.

If someone else has closed the cell door (locking it), he will Ready the attack action, if the quaggoth in the cell moves into the open.

Attack: 19 Damage: 5

Eldeth and Tozer sense the time has come for them to leave the guard tower. Eldeth, keeping her longbow in hand, dashes across the bridge; Tozer does the same immediately afterward. Upon seeing the quaggoth's decision to flee into the cell, Tozer focuses his attention to the north, hoping to gauge how Topsy and Turvy are faring. 

Jimjar pulls the cell door closed, locking the quaggoth behind bars. 

Perception check to see what Topsy and Turvy are up to.

Buppido is weak from blood loss. He stays put, leaning on his hooked spear for support.

Perception for Tozer: 15

Sarith spreads out his Dancing Lights illuminating all of the stairs and the landing, just in time for Tozer to be able to notice Topsy and Turvy leap off the platform into the waters below.

Ront dashes across the bridge (to N9) after looking at Tozer and growling, "Coward."

Beegred moves into the cell, shoots the quaggoth and retreats back to the stair.

Jimjar moves (to N11) and closes the cell door, locking the quaggoth inside.

Eldeth dashes across the bridge (to M10).

Buppido leans on his spear and breathes heavily, bleeding profusely.

(I'll wait for Derendil to act before Tozer, as there's no room past the bridge.  Map incoming...)

(Totally  missed it was derendil's turn again.  I'm all screwed up with being off all week for the holiday)

With the last visible quaggoth locked in the cell, Derendil moves down the stairs towards the landing from which topsy and turvy jumped.

(Is it still slick?  Can he use extra movement or something on those steps to avoid a check to fall over, or to get advantage on it?)