I was doing new dungeon, got to end part but then I did drop trough from into water, I tried esc/escape and it teleported me back to entrance, is there any way to get back to boss room ? I tried to run back but in middle of a way there is force field that does not allow me trough it.

Yes you can ... but this "dungeon" it's as always from PA = EPIC FAIL.

You need again drop 10x "blue" and make horn and again kill boss no 1 to drop heart and merge horn + heart. Then you can enter boss no 2 zone and .... I  don't know how but  I managed to get through the barrier to the last room after other party killed boss no 2.

You can climb over the barrier using a cliff face on the left of the intruder room to get back to the portal to the final boss room.

Thank you for help guys, it was easier to just do everything from beggining. I feel bad for people who will start doing quest now, zone is empty.