Stealing from a greater vault

[Cactus]

I'm currently clearing a fire vault in the frost giant caves with a mindcrafter and have spotted the bracers of war. I've killed about 7 of the ancient dragons so far, luring them out one by one and killing them carefully with confusion blast. Now the Wyrm has woken up and I don't want to risk a fight yet. Especially since it is very unlikely he can be confused just as well as the ancient deagons.
Lacking a scroll of magic mapping, I'm not sure how the layout looks like. I never remember these things. Can any of you tell by the monster/item detection screenshots, if it's the kind of vault where you have one tile below the treasure and you can safely teleport in? Is there a free tile below the bracers, the weapon or even both?
Thanks in advance!

Screenshot:

[Blasphemous]

Yes, there is one free tile just below the bracers and below the rightmost gold pile.
However, if that dragon has been alerted somehow, you have a 50/50 chance of teleporting to that spot.
Otherwise you're free to go.
Here's what the top left corner looks like:

#############
#~###(#####..
#.######.....
###..........
#............

[_Ln_]

Equip a ring of invis, teleport into the corridor above artifacts and zap the guardians repeatedly. Teleport on artifacts, grab them and be off.

.X...X...............
#############
#~###(#####..
#.######.....
###..........
#............

Stand on X'ses and use Mind Blast below. Personally with 32 PV and 150 hp I would advise against teleporting in the confined rooms. After a while you will automatically "open up" the secret entrances and will be swarmed from below, possibly be the wyrm.

Naturally, if I were you, I would clear the vault clean

1) Confusion Wave
2) Mind Wave x5
3) Recharge PP
4) Repeat steps 1-3 if necessary
5) Clear remaining fire elementals with Telekinetic Blast (as they are immune to telepathy)

Pro tip: Telekinetic Blast will not break invisibility, so you are mostly safe.

EDIT:
You just had to make me itch to play a mist elven mindcrafter again, hadn't you?
I hate you.

EDIT2:
Wait, you are level 25, which means you have Greater Telekinetic Blast. It cannot be shrugged by anything. With careful PP planning, you will be able to overcome wyrm's regen for some sweet xp. However, you will not be able to target it outside of LoS.

[Cactus]

Thanks both of you, that's great news. After stealing the bracers I might feel comfortable to clear the rest of the vault.

Another way of doing it came to mind when I saw your approach of using mind blast through the wall. That would be confusion blast through the wall, then check each round with eyes of the mind if it has stumbled on the free tile, then teleport directly on the artifact.

Wait, you are level 25, which means you have Greater Telekinetic Blast.

That comes at level 30. So maybe I just get the bracers now and leave the wyrm for later after hitting level 30.

You just had to make me itch to play a mist elven mindcrafter again, hadn't you?

Actually, this is a mist elf, too. I abused potions of exchange though to adjust the stats. On the other hand, I use whips only, so I think that evens things out a bit. The bracers of war fit in perfectly here (and later cat ring and air orb)