1 - The missing villagers of Tar

Well aware of the fact that you would be in a bad situation if you got caught while in that tunnel, you all advance with exceptional coordination and stealth.

As Tianni reaches the opening, she can observe another one of these mine caves with a large stalagmite at its center. The opening where you are is near the ceiling and seems to have been revealed as some part of the wall collapsed. And while it would be an easy climb down, jumping would actually be dangerous: you are currently standing somewhere around 16 feet high with lots of rocks on the ground.
The voice comes from behind the pillar, where you can glimpse some arms movements without getting a good view of the creature. From what you can see, it might be a kobold. And while you are not able to understand what is being said, you recognize that the orders are given in undercommon. There are different kind of spiders that goes as she dispatches tasks: the spiderlings that you already met, giant spiders, and something that looks like a weird kobold with a spider abdomen attached in his lower back. Nothing Tianni or Sedror have met or heard of.
None of the creatures you can see seems to have noticed your presence, but it probably only is a matter of time!

Unless someone stops Tianni, we're now in combat and you benefit from a surprise round. What do you do?

Everyone, Tianni jumps out of the opening without giving it a second thought. As she lands with a loud, unmitigated noise, you know that you have to either use that surprise element or hold back to engage your enemies later, leaving her alone.

Tianni, the moment you hit the ground you start running toward your enemy. You hear the voice shout short orders, probably wondering what the hell is happening. You go around the natural pillar on the left and end up right behind the strange humanoid creature.It look like the ones you saw through the opening and that have been sent to some task, with two major differences. The first and most obvious given where you are standing is that its spider abdomen have been severed from its body and that a large scar sits where the abdomen should be. The second one is that the creature is holding a dried human leg that it uses as a staff and wears various trophies from its numerous victories over humanoids, most of them being bones and trinkets.
Your attack, fulled by the rage of seeing such a creature parading with proofs of the many innocent lives it took, goes exactly as you intended it to go : through the disgusting creature. It roars/shrieks with a terrifying sound, turns around brutally while your sword still is in its body and gives you a look of pure hatred.

The battle map (that you can find here):

Let by Tianni, Mee'haïl and Sedror jump out of the opening and try to get rid of the enemies before they get a chance to react.
The barbarian, all rage and fury, jumps out and bolts toward the closest enemy that happens to be facing Tianni. It has a large, open wound and roars and curses in its dark language, ready to jump at Tianni's face and do gods know what. With a single powerful slash, two of the creature's limbs fly away in a nasty splash of ocher blood.
At the same time the scaly dwarf Sedror slides down on the rocks while casts a spell, and releases a blazing fore bolt that goes straight at one of the approaching spiderling. Touché!

The arrow flies off Bug's crossbow and goes straight to the menacing creature facing Tianni. The bolt hits the most deadly of all targets, and you simply see half of it stinking out of the creature's head. A horrible shiver runs through its body and it falls dead on the ground, clearing the path toward the incoming enemies.

Tianni, there's a spiderling 15ft away on your left that was eating something on the ground and that is now running straight at you. Two others are rushing into the cave from the path in front of you. There's something else following them, but you can't see it clearly do to the light that comes the outside, right behind it. What do you do?