I think I might be last to get there as I was guarding the retreat, but if there are any left when I arrive: charge!!
What Shadowfacts said.
I thought Bitur had effectively sent Hraedsig up front with Gwaelur. As that was what I had in my mind I will go with it.
Gwaelur and Hraedsig charge the goblins with Thoroncir and Elfstan behind. There is now plenty of light and no more goblins are visible. Mulligan engages the one that stuck her in melee and they both miss.
The other 4 brace for the onslaught but are quickly beaten downed and killed by the four party members. Ghân is headed for Mulligan right behind Gil-Gandel with both swords out. Mulligan stabs the goblin and he drops injured and sleeping. Ghân heals Mulligan with a cure light. (assuming that she already ate berries today, otherwise let me know and we’ll change this.)
Only had the one Goodberry today, so no need for the Cure Light.
“Thank you Ghan, they are most welcome.”
Mulligan looks at the galvorn armour she is wearing. “This metal is supposed to be really hard, I just wish it covered the rest of me as well.”
“Here’s hoping its quieter between here and the door.”
Thoroncir picks the strongbox back up and nods towards the door. “Let’s find out!”
So, do we ask this one some questions, or do I put him out of my misery?
Gilraen, “We should tie him up and carry him out. As we are leaving there is not even a weak excuse to execute him summarily. I’ll need to see to his wounds when we get to a safer place.”
Brin rolls his eyes a bit at this but says nothing. He did use enough caution that Thoroncir does not see it.
Thoroncir doesn’t mind if others disagree with Gilraen, so long as they do it respectfully. A little eyeroll now and then is all right - he’s been tempted to do it himself!
Let’s do a quick search of the room while we’re binding the goblin.
That’s fine by me too.
I’ll tie the goblin up, while the others look around. Someone else gets to carry him though. 
Brin, “I will carry him. At least there are no more stairs.”
The north east corner of the room has 7 sacks weighed down with bulky stuff. There are also 12 spears of good quality.
Why carry him out? He’s injured and drugged. Leave him. He’s no threat, and what’s he going to tell his friends? “Men, elves, and dwarves came by!” The enemy already know that.
“Careful he doesn’t bite your ear off.”
Brin, “I placing my trust in Mulligan to have him well trussed and muzzled.”
To Deor he says, "Hey, I don’t care. I would rather carry some sacks then a goblin. Up to our leaders. "
“My lady said she wished to attend to the goblin’s wounds,” Sir Thoroncir says. “It will be safer to do so outside. He comes with us. I will carry him if no one else wishes to, so long as someone else carries the strongbox.”
The knight-errant will take a quick but careful look in the sacks. Would someone like to pick up the spears, or should we just break them to deprive the goblins of weaponry?
He might know something useful (numbers / leaders / secret passage / treasure room).
Ghân will cast Detect Magic on the sacks + spears.
One spear is magic and appears wooden except for the black iron head. The wood is stout clean ash.
Brin will still take the goblin; he figures it weighs less than the strongbox. He just does not care what we do with said goblin.
Who is grabbing the sacks? No time to look, Gilraen’s song end and in 9 more minutes it will be done. We need to at least get back to Miron.
Don’t worry Brin, he will be well trussed.
I’ll take a sack along with me, who knows what might be hidden in such things. Although I can’t wait to get my hands on that strongbox. 
“Everyone, please grab a sack apiece, if you can,” Thoroncir calls. “Drop it if you must use your weapon. Gil-Gandel, would you carry the magic spear? Come, let us make haste to quit this place.”
Gwaelur will grab a sack and encourage others to get a move on.
Hraedsig is not proficient in spears and is not interested in random loot, so he’ll defer on carrying a sack in order to keep his sword out and ready. He’ll carry the magic spear for someone else if they need him to, though. No sense in leaving that behind.