The lobby area should have some ambient noise such as helicopters taking off, trucks driving past, soldiers conversing, fixed-wing aircraft blazing past overhead.
An example of what not to do, would have to be TAVR's menu area and map selection area. You're in a dark compound with nothing going on around you.
A good example of ambient "base noise" would be in Onward. Soldiers whistling, gunshots going off, soldiers marching, etc.
(Fuck onward tho)
https://www.youtube.com/watch?v=bPz0kk1qFQw
We are playing in VR, we should be immersed in a world that the average person will never get to see.