I think they only need to run away with a full pot of the nitric acid. The resurrection "etching fluid" is pretty easy to make besides that.

Or maybe, the goal is to actually destroy the cave so Tsukasa can't use it anymore. Senku must know another way to make nitric acid, they already have electricity and know how to make ammonia. I mean, they just revealed he's been using the Master of Handicrafts (Yuzuriha) to piece together broken statues. Senku's been running long-game psychological plays well before Gen switched sides.