(Jorin was partially buried as well. That athletics check was to dig himself from the ruble and standing upright. Second Wind has him at full health.)

The only thing Drusk can do is try to dig himself out. Takes another 5 damage from the ruble. Athletics: 8

Hildigrim is up.
(After that, the 1st Worm that is in front of the party goes, then Spar & Quillary, then the 2nd Worm 120' back.)

Hildigrim moves back to where Drusk is buried (position +55).
He asks Volo (owl familiar) to do a flyby to Help while Hildi shoots an arrow at YW1 (with sneak damage).
As a bonus action, he will Help Spar's next attack on YW1.

• Attack: 28 Damage: 36

The YW1 move 5' closer and attacks the nearest target: Quillary.
It shifts slightly sideways so it can bite and use its stinger.
(This immature worm isn't large enough to swallow Quillary, but it still has potent venom in its stinger.)

• Bite Attack: 24 Damage: 20
• Stinger Attack: 22 Damage: 8
• *If* the stinger hits, roll a DC 14 CON save. 14 poison damage for a fail, 7 for a success.

Spar and Quillary are up. (Then YW2, then the next round.) Spar has adv. on her first attack on YW1.

What he said.

(Yeah, that's a lot of arrow damage to retcon! :)

Spar fixes the worm with a withering, "now why'd you have to go and try to ruin my day" look. (BA Hexblade's curse.) Her eyes narrow, and she tightens her small buckler in her hand and her shortsword glints in her other hand. She races forward without a sound and leaps into the fray, seeking to chop the thing's head off.

Attack: 21 Damage: 10
Thirsting blade Attack: 25 Damage: 9

Quillary steps into the attack, dodging one blow and taking the other on her shield. Her cudgel comes out and after a light tap to the cat skull on her forehead, it grows a frost of ash that sloughs away, leaving it shiny and hard. She brings it around to strike the worm, a fierce smile on her face.

Move: no
BA: Shillelagh
Action: attack YW1 with magic club. Attack: 18 Damage: 8 magical bludgeoning.

Reaction: spores attack WY1 on its turn, Con save DC 16 or 5 necrotic damage 

A full grown purple worm has a shell like plate armor. Fortunately, this young one is still soft, with a shell only like thick leather.
Everyone hits, for a combined (18 + 10 + 9 + 7) 44 damage.
The hits are showing damage, but YW1 has a lot more health left.

YW2 surges towards the group, moving + dashing as fast as a sprinting human, the debris in the passage not slowing it down.
(It is now at position +0. Next turn it will reach Drusk, although it will still be dashing.)

New round. Jorin and Hildigrim can both act.

Jorin moves to intercept, roaring ferociously and swinging his blades in deadly arcs!

• Movement: Up to 40 ft, in melee range of the worm
• Bonus Action: RAGE
• Action: Battleaxe!
  • First Attack: 28 Damage: 14
  • Second Attack: 27 Damage: 16
• +5 radiant damage to the first strike that lands

(aww, should have reckless'd)

Once again asking for Volo's help, Hildi fires another arrow, trying to finish off one beast before the second reaches them. As his arrow sails through the air, he calls out another tidbit of advice to Spar for her next attack.

Attack: 26 Damage: 13

Bonus: help Spar

Drusk takes another 5 damage, and continues to dig himself out (still need 2 successes). Athletics vs DC 15: 9
(OOC: He still has 35 HP. It would be bad if the other worm knocks him unconscious, while he is still taking auto-damage from being buried.)

Jorin misses with his first blow, still getting the rock dust out of his eyes. But his second blow (17 damage) and Hildigrim's arrow (19) bring the total damage to 80.

YW1 is spraying gouts of slime and fluid from its heavy wounds (like buckets of squished bugs), but it is still vigorous in its attacks.
Still targeting Quillary.

• Bite Attack: 19 Damage: 20
• Stinger Attack: 21 Damage: 7
• *If* the stinger hits, roll a DC 14 CON save. 14 poison damage for a fail, 7 for a success.

Quillary is up, then Spar. (Then YW2.)

(Did YW1 save vs Quillary’s spores on its turn? That 2 points of damage might be critical!)

Quillary grunts as the bite just rakes her arm, but her shield manages to intercept the stinger. She swings again, her spores swirling.

Move: no
BA: no
Action: attack YW1 with magic club. Attack: 10 Damage: 7 magical bludgeoning.

Reaction: spores attack WY1 on its turn, Con save DC 16 or 3 necrotic damage 

(Oops, I did forget about the spores.) YW1 CON save vs. DC 16 spores: 19

Quillary's club strike misses, as the worm gore spraying around sometimes makes it hard to see.

Spar is up. (Has Help advantage on first attack against YW1.)

Soar looks at Quillary and then back at the worm with a “Really? Her? When I’m right here?” expression. She tries to get its attention again with a hex, and two more attacks.

Attack: 18 Damage: 12 plus 1 damage from Hex
Thirsting blade Attack: 25 Damage: 9 plus 1 damage from Hex

(Spar's first swing went from a miss (2 on the die) to a critical (19 with the curse), so Hildigrim helped a lot.)

Spar is momentarily blinded by more worm gore clouding the air, but she hears Hildigrim tell her to strike forward now! After a solid strike into its head, she makes a second stab into its body as it rears up.
(27 damage for the critical first strike, 12 on second)

Spar and Quillary avoid the YW1 body as it crashes the the ground. It lets out an audible sigh (along with a cloud of really stinky breath) and expires.

The other worm move+dashes, stopping within melee range of Hildigrim.
It also notices the pile of debris next to it that is moving due to Drusk trying (futilely) to dig himself out.

New round.
YW1 is dead.

Jorin, Quillary, and Spar are at position +65.
Hildigrim is at position +60. (With YW1 dead, he now has room to move forward, but right now he is in melee range of YW2.)
Drusk is still double-buried at +55.
YW2 is at position +55 to +60 (large sized).

Jorin is up, then Hildigrim. (Then Drusk, Quillary, Spar, then YW2.)

Spar finishes the cut and rolls out of the way as the worm falls, ending the roll in a crouch. She gives Quillary an appraising look, and whispers, "thanks" and, if she can, moves closer to the other worm, blowing a scraggly strand of hair out of her eyes, which may or may not have a drop of worm goo stuck in it. She bangs her buckler with her sword and tries to gain the new worm's attention.

(If she'd notice YW1 fall and hear the other approaching, and could still use movement, that is.)

Quote from rkmobius >>

Spar finishes the cut and rolls out of the way as the worm falls, ending the roll in a crouch.

(If she'd notice YW1 fall and hear the other approaching, and could still use movement, that is.)

(You could move to position +50. That would keep YW2 out of melee range for both Drusk and Hildigrim, but still force the worm to use Dash instead of an attack.
Assuming Spar does that, Hildigrim can move around without the risk of AoO.)

On Drusk's turn, takes 5 damage, and ties to dig out (needing 2 successes). Athletics vs DC 15: just failed with a 14 (game log)

(Do we know where Drusk is, and is digging him out feasible?)

(Going ahead and posting.)

Hildigrim grins a satisfied grin as he watches Spar finish the worm with his encouragement. But his grin slowly turns into a frown as the newcomer does a fancy roll and then ends up running around him. As his eyes follow her, his head swiveling, he finally notices how close the second worm is getting and how Spar has placed herself between it and him. The halfling's eyes widen, and he skedaddles into the spreading goo puddle that is the remains of the first worm before spinning and firing another arrow, this one at the fresh beastie that is now being buzzed by the tiny Volo. "Do it again, m'lady!" he calls.

Movement: 25 feet away from YW2

Attack: 26 Damage: 20

Bonus: help Spar

Quillary runs at the worm, but before getting too close turns to keep her distance and get close to Drusk's position. Then she throws herself at the ground in a cloud of spores that clear to reveal a giant badger (wearing a ring!) digging furiously at the ground where Drusk is buried. The dirt flies.

Move: to get close to Drusk, trying to avoid worm but taking as direct a route possible to save at least 10' movement, so if she has to run next to the worm, she does.
Action: Wild Shape into Giant Badger
Rest of move (if available): Burrow Speed 10' or less to reach Drusk and free him from debris
Bonus Action: nope

(There's some movement math to do here, with 30' of movement, or 10' of burrowing, and some conversion, but without a real map I can't do it, I just know that Quillary is at +65 and Drusk is at +55 which sounds like 10' so there should be enough of everything left over to do this plan? DM adjudicate! ;)