When you get to quest card 2B in the 7th level scenario, do you have to reveal extra cards at the end of the staging step just once, or for the rest of the turns until the game ends?

Thanks very much for your help!

That would be for the remainder of the quest after each staging step (step 2 of the quest phase)

I would also add that this quest is pretty difficult for a 3...heck i think it's just about as hard as the pit. I think it's very challenging and fun. I've gone 1-1 against it with my partner and each time we each had at least 2 enemies engaged per turn every turn of the game, and there were some hairy situations when cave trolls popped out of the encounter deck.