Into the Barrier Peaks

Etna
Taking a quick stock, you see that none appear injured or under assault. The sun has just begun to crack the eastern sky. Following the gaze of the others, you see that the metal valve blocking the smaller cave, high on the hill, appears to have opened.

Bram
It is more pre-dawn. It is perfectly acceptable to assume, if you deem it your normal routine, to have risen a bit earlier to study.

As you all approach the base of the steep hill, you see that the upper cave door has, in fact, opened. You cannot see much more than that from this vantage. It is a steep hill, and will require two athletics checks to ascend. If a rope is secured at the top somehow, the two checks are with advantage. It is 100 feet, should magic of some kind be used.

Caedwyn, Merriweather
At the top of the hill, you see that the metal valve blocking the entrance has, indeed, slid away and revealed the inside of the cave. The entirety of the space is metal, including the floor which is made of of a strange metal grating. The space in the cave is roughly 20 feet wide and 10 feet deep. The far wall looks like it is a thin line running down the middle. The entry wall behind you looks slightly curved.

Securing the ropes together, you drive a few pitons into the stone and toss it over the side. A few minutes later, Hraefn scrambles over the top, followed shortly thereafter by Ilwyn.

Hraefn
The room is strange, unlike anything you have ever experienced before. Examining the area from outside the entry portal, you cannot seen anything that would indicate it is trapped or otherwise poses an obvious hazard.

You all climb up to the top of the hill, Bram struggling as the rest of you manage to pull him the final few feet. Taking stock, you all see the strange metal entry for yourselves. The outer metal surface is dark grey in color, while the interior is darker. Immediate observations indicate no other exits as you all follow Hraefn inside.

The far wall, upon examinations, appears to be much like the outer valve, though instead of one large door, is actually two doors as evidenced by a thin line vertically bisecting it right down the middle.