Hey!
Where are the environmental sounds on the map? Nothing makes any noise except the truck engine. Otherwise there is absolutely deathly silence on the map (except for the truck). In other community maps (and all of maps by Valve) from other authors that have been added (for example, Thera, Memento, Pool Day), there are sounds of air, sea (on Thera), sounds of birds or dogs barking in the distance.
Here, given that this is a hangar, you need to add the sound of some industrial facility, for example, the ambient sound from Nuke (like on the Ramp). Without these sounds, the atmosphere deteriorates, everything feels somehow plastic.
Add it if you don't mind. Look at Memento, they use sounds (assets I guess, I'm not an expert) from Inferno, which change in different places on the map (somewhere the sound of water, somewhere birds are singing or insects are buzzing). Here we just need to add a sound similar to that from Nuke (inside the building). And, if there are ready-made assets, some sounds of equipment, sounds from lighting lamps. At the top of the hangar there are many fans spinning, and the atmosphere is somehow sepulchral and quiet. There should be light ambient sounds, like on Nuke inside the complex. Now it’s like there’s a vacuum here.