The key and lock aren't accustomed to the amount of force being used on them and the key snaps in the lock. However, the bolt seems just as brittle as the key, forcing it open seems like an option.

(Make a STR check)

Wolfstine just tilts his head with a frown thinking he shoulda done this. He tries himself to open the door

Strength check 24

With a loud echoing crack the grate swings open, the path to the stream is accessible. 

Frilneiros will move to be in the front of the group again once the door is open, looking at their surroundings. "Are we keeping this marching order?"

Gus 

“Seems fine t’me, Fril,” Gus remarks, eyeing the barbarian’s giant axe. He looks to the others, shrugging. 

Wolfstine shrugs "No problem, but if we use this tunnel for refugees we'll have to deal with the rats first when we get back here"

Dropping the torch readying his rapier. He follows behind the Kobold thinking with Frilneiros's small size, they should make a good team

he keeps his eyes, ears sense of smell and other senses active searching his surrounding

Perception 6 damnit someone farted🤣

Quote from Stormbringer4729 >>

Wolfstine shrugs "No problem, but if we use this tunnel for refugees we'll have to deal with the rats first when we get back here"

Dropping the torch readying his rapier. He follows behind the Kobold thinking with Frilneiros's small size, they should make a good team

he keeps his eyes, ears sense of smell and other senses active searching his surrounding

Perception 6 damnit someone farted🤣

 Gus

Looking at Wolfstine about to drop the torch, he remarks "Maybe ye should let that torch land on the rat's nest, laddie?  No sense wastin' a perfectly good torch." 

Wolfstine shrugs

"Gus? After all that effort in avoiding them?"

He looks in askance to the others

Gus

”Well I ain’t the sharpest axe in the shed laddie, I be only thinking that if we’re bringin’ a mess o civilians down ‘ere, I’d hate to have any chompers eatin’ on ‘em, eh?  Jus’ a thought, specially if we’re on the run on the return trip.”  
Gus isn’t lying, he isn’t too bright but he won’t be angry if y’all disagree. :)

"We should deal with one thing at a time. I fear that the villagers may be harmed if we take to much time though." Frilneiros says as continues to walk ahead.

"Rats are the least of our worries, Gus, Our resourses are finite."

Wolfstine moves on

(Next scene please)

“I am in agreement. We would make haste and do what we can to aid the villagers and not get tangled up with these rats.”

With that, Celadrim holds his place in line and follows right behind Frilnerios. 

As you pass through the exit into the river you are beset by an ambush alerted by the breaking of the grate.

(Roll for initiative)

 initiative 7

Gus

Initiative - 4

13 initiative

Celadrim 

Initiative: 18

Inititiative: 3

You are greeted with a volley of rocks from slings.

The first two shoot towards Frilneiros

Kobold A Attack: 12 Damage: 5

Kobold B Attack: 24 Damage: 7

The second two fire towards Wolfstine

Kobold C Attack: 15 Damage: 3

Kobold D Attack: 5 Damage: 6

There are two cultists readying Scimitars waiting to see if any of you get close enough to them to hit.

Harbinger Kane shakes off his surprise first and makes his move.