I was worried it would be noisy too, but we couldn't hear anything. I think it's a solid brick wall separating the lounge from the room. Also, the sitting room is the only room immediately abutting the lounge wall. One of the bathrooms is behind the elevator bank as well.

I'm not sure if the map is updated or not since those areas are part of the lounge, but do seem kind of like separate rooms/sitting areas even now.