There's water breathing and levitation available, most likely accessed by consumables. Good luck actually
finding either of those, though. In the couple dozen I ended up killing off before giving up, something like two of them found any sources of those, and one not until like level 5 or 6 of the dungeon. Meanwhile four or five ended up in situations like you describe, with murderterrain blocking the only route forward and no means of doing anything about it. One or two on the first bloody floor

I think my favorite WTF re: the generation that I hit, though, was the time the first level of the dungeon had literally nothing on it. No items, no unusual terrain, no creatures. Nothing. It was completely empty except for the player, some doors, and the stairs down. Character in question died on the next floor fighting something it couldn't run away from -- one of the dog variants that like to spawn early, iirc. -- 'cause, y'know, it was naked, unarmed, and had zero consumables to help survival.