Originally posted by Hydro Boom:

alr thank you all I was confused if I had missed a room

the entire reason, as good programmers you DON'T do this. Apparently they did not read the memo. I have written before about it. It leads to confusion, unnecessary chances. Designers don't typically put you in such a predicament. It's bad judgement. And also you can get sound from the surface in some, esp ones that cross a biome border(below ground).
In fact silly enough, but technically true, you can cross a biome underground for the first time and get the banner notification. But weather sounds do sometimes play down there. Which I also have written about. And just happened to me today. Winds that are normally part of the Mtn biome can be heard underground in the chambers. ;p