Jaylen describes what he sees outloud, kind of to no one and everyone all at once, deep in concentration

Arcana: 21

Sleight of hand: 21

Jaylen; in the sanctuaries of your sect, you have seen these type walls – magic flow, brought forth from runes. They were used to separate and hide parts of the sanctuaries, either to provide security for its followers or to protect texts, dangerous knowledge and artifacts.
You helped inspect such walls when staying in the sanctuaries and know that destroying enough runes will cause the wall to disappear. They are also passable as long as one convinces themselves that the wall is not there – usually by closing their eyes and walking through it.

It only takes Meep a short moment to find and take Jaylens gold piece.

Pocketing Jaylens gold piece, Meep would head back to his box. 

Assuming he is relaying this out loud as he said, I say to myself "There is no wall", close my eyes and walk through it - right at the edge so I can hopefully get out of sight on the other side quickly.

"Yes, very good Dhara! Come on, let us see what mysteries await us on the other side!" Jaylen follows Dhara confident in his knowledge the wall is an illusion and walks through.

(Dhara, roll DEX save with disadvantage)

Dex: 7

(Man can't catch a break on these rolls!)

As Dhara closes her eyes, convinces herself there is no wall and starts to walk towards it, Jaylen can see the abjuration auras closest to Dhara turn to evocation auras and disappear. Before he can say anything, and just as she is about to pass through the wall, 3 magic missiles hit Dhara.
(Dhara takes 7 points of damage)

Meep picks up his box and turns to those still messing with the wall giving a shake of his head before continuing to the tunnel ahead.

Stealth 8 (oh no) 

Everyone notices Meep shake his head and turn to continue down the tunnel.

Did I make it through the wall at least?

(Dhara, Roll constitution - DC8; on success you ignored your pain and have passed through.)

"Dhara are you ok? Perhaps we should try and destroy these runes to dispel the illusion of the wall? Then we could see the other side without blindly walking into whatever device is firing those bolts of arcane energy."

(just for clarification, to Kamos, it appeared that Dhara walked through a solid wall?) 

(IF Dhara rolls CON 8 or higher, then yes, she walked through. Otherwise no.)

Too late.  See you on the other side (I hope)

Con: 12

Finally.  Also when I get through I'm lookin' for a place to hide ASAP:

Stealth: 9

(Ninja mode!)

Dhara disappears through the wall.
There doesn’t seem to be anyone there to hide from, but Dhara hugs the wall and blends with the shadows.

Past the illusion wall the room continues for another 20 ft, with a man-made, stone block wall standing parallel to the illusion wall. A heavy stone door sits in the middle of stone block wall. There is something written on the door but you can’t read it.

Kamos: (to the party) "did you all see that? she just walked through the wall!"

Can I open it?