ToME: the Tales of Maj'Eyal

If I stay, the ally seems to grab all the XP. If I leave, I get an error message when the quest resolves. Is this a bug?

I'd like to play a Dwarf Wyrmic, but not if the very first action threatens all subsequent game stability in that playthrough.

Yes dont leave you're not supposed to be able to do so (fixed in next beta).
And do not worry for exp, the quest is specially engineered to account for that. Just play and you'll end up the level you should

In beta 23, as a dwarf, you will start in a dungeon called "The Escape from Reknor". This is laid out similarly to Reknor, but is a separate zone. You start on dungeon level 1. You start with a Berserker companion who will follow you around.

You must seek downward staircases, which are placed randomly. You keep going down until dungeon level 5. There, you'll find a boss. The boss will drop a rod of recall, but you don't need that. (I don't know what happens if you use it -- I didn't dare try.) Keep searching that level, and you'll find another downward stairway. This will lead you to the city of Iron Throne.

The city of Iron Throne has 3 exits. One leads to "The Escape from Reknor". The second leads to a different dungeon called "The Deep Bellow". The last leads to the world map.

Any time you re-enter Iron Throne, you will appear on the stairs leading to "The Escape from Reknor", no matter which direction you came from.

Nothing happens if you use the rod of recall off the boss - you still have to take the stairs. This seems to be true through this whole dungeon.

Also, when you are playing a Durf, talk incessantly on the chat channel about how nice it is to have an extra store available (just to make other people jealous).

shooth - Team Durf