(Leofir could dash as an action and as a bonus action to get to the end of the hall over the cages, otherwise he does not have enough movement.)

Yuron will follow Leofir. "Should we be ready for whatever is on the other side of the door?" as he pulls his hand crossbow.

13 Acro

4 Athlet

Rey scoffs. "Bah, caught this cage door for nothing!"

Leofir will dash then.

"You saved Yuron and me Rey! Let's get out of this hallway."

Shaa will stay close to Leofir and follow as fast as he can. 

He also casts Detect Magic. 

"And you looked like a badass doing it"

Hahaha. Rey also follows the others on the way through the hallway, offering boosts and help over cage tops. (I'm a little lost with picturing this scenario so just lemme know if I need to roll anything)

Athletics 18

Shaa senses that the dagger that Leofir picked up is magical. The party runs towards the end of the hall, although only Leofir is fast enough to reach its end. He sees the robed man, who promptly casts earth tremor.

(Leofir: DEX save DC 15 or take 5 damage and fall prone.)

(The party is up again. Most of you are about 20 feet behind Leofir, just behind two fallen cages.)

(Leofir also has no idea the dagger is magical)

Leofir feels the ground shake and attempts to do a split in mid air, using the walls as foot holds

DEX ST 16

Is the man behind the slit, or in full view at the end of the hall?

How spread apart are the bars? Yuron will move his 30' forward (halved for difficult terrain I assume?) and if the bars are open enough he will cast hunters mark and take a shot at the robed man if he's within 60'.

Attack: 27 Damage: 18 if disadvantaged 19

I'm sorry whoever I'm shooting, hopefully I'm not within 60' lol.

Rey will use his feline agility and dash action, granting him a move speed of 120' in an attempt to catch up to the man. Parkouring as much as possible.

If needed, athletics 14

The man is behind the slit at the end of the hall, and Leofir, who has passed the end of the wall, can see him clearly. Leofir keeps his footing. Yuron has no sight line on the man, and rushes forward, nearly catching up to Leofir as Rey zooms past. 

(Shaa)

Shaa will move forward more carefully.

He can t see anything yet so he wants to get to his companions. 

The robed man casts shatter focused on Leofir and Rey. The cages crack behind them as a sharp ringing tone fills their ears. They take 19 thunder damage (CON DC 15 for half).

(Everyone is up)

Yuron is assuming the slit is in a door (or hidden door) so if he can get up to the door on his turn he will try and put his shoulder into the door to break it in so the others can advance. If not he will dash to the door "Get in there and take this chump down".

1 Athletics

Oof, con save 24

Rey winces at the ringing in his ears, roaring in pain, filled with rage. His eyes widen, pupils dilate and he keeps pursuing his target.

If he can get within 5', Rey will grapple at adv; 16 10

If not, he'll peg a javellin at him: 13 dmg 6

Shaa will use the path Rey weaves trying to get closer to the man. 

Leofir looses an arrow through the slit at him.

Attack: 16 Damage: 11

Con ST 18

Rey and Leofir are out of the tunnel and can clearly see the robed man. There was no door blocking the path, the slit is next to the exit. Yuron and Shaa are at the end of the tunnel but can't yet see the robed man. Yuron and Shaa rush towards the exit to join the fight. Rey (9) easily grabs the man. Leofir (22) shoots an arrow that penetrates a layer of armour. The robed man is bleeding in several places and looks close to death.

 A spell forms at the man's fingertips. The ground trembles and dust falls from the roof. You all take 7 bludgeoning and fall to the ground (DC 15 DEX to negate).

(Party is up)

Dex save: 19 if Rey falls, he'll attempt to bring the man down prone with him.

Athletics at adv 23 18

"Just... Give up already!" Rey growls in the man's ear. Squeezing him tight, hoping he'll pass out.