Murphy's law struck me and I failed disarming a chest in level 10 and was teleported I don't know where but not in a wall ! Monsters are level 10 monsters but the map doesn't look like it. No door, no pit, no stairs, nothing. My cleric is dying but still has locktofeit available. I don't have Malor (which wouldn't work anyway I guess) but I have the diadem of Malor.

Anyone has a hint on how to get out without ressorting to locktofeit ?

A few ways:
* Go through a door, kill the monsters (or you could just quit out of the battle if you really don't want to fight it), then turn right. This will take you to a teleport to the start of the floor, Going right from here will warp you back to the castle. (This won't work if you teleported to Werdna's hallway.)
* Use that Diadem of Malor. This will, I believe, cause it to turn into an ordinary helm, but will at least allow you to escape without losing all your items. Teleport up 9 floors to go to level 1, from which it should be easy enough to leave the dungeon. Malor will work when cast on level 10; it only fails if you try to teleport onto the floor; teleporting to another floor should work.
* Defeat Werdna and take his amulet. Use that amulet to cast Malor, which will allow you to teleport up 9 floors. Just be aware that the amulet is cursed, and when you leave the dungeon you will lose all your items (assuming you're playing the new remake or some other computer version; console versions tend not to take your equipment in this situation).

No door so that option is not possible. I'm roaming outsides of those sections.

i was about to use the Diadem and choose my parameters (9 level up) and hitted cancel and the diadem transformed to a normal helm ! What a shame !

Ok, here we are almost 2 months later. I was able to hack around and restore my saved game prior to using the Diadem of Malor. I did also update the game. There are multiple bugs happening. When using the helm, if I hit cancel it turns into a normal helm anyway. When using it properly, I see the teleport animation but my party doesn't move at all. I tried teleporting to another location on same floor (level 10) and it says " Failed to teleport ". If I teleport 10 level up, I don't see any error, but I don't move at all. If I teleport down, most of my party dies obviously as in the original game but i'm still in level 10.

Can we expect a fix for this or I have to start again with 0 GP and 6 fresh character ?

Try teleporting 9 up and see what happens.

Alternatively, if you have a backup of your save, try getting into a random encounter and teleporting out of it. This should take you to a random location, not necessarily on that floor.

Loktofeit, if it works, will allow you to keep your characters, but not their equipment and only the least significant digits of their money. (Well, I believe the money that has been collected automatically in town will be spared.)

The helm turning into a normal help when cancelling is the original behavior, I believe, as is trying to manually teleport to any location on level 10. (DUMAPIC shouldn't work either, I believe.)