Hey S4drax, Thanks for playing, and glad you enjoyed it. The game was made in such a short amount of time, I really didn't have time to make and think of everything, So the reason you can't use the guns of the soldiers in the basement, is because when you exit the starting room, you hear gunfire coming from the basement, the guns are out of ammo. Hope that's a good enough explanation for you.
However, if anyone reading this would like to know why the guns aren't usable. The game was made in about 5 or so days, and I didn't have the time or the animations or the sound effects or the particle effects or the gun folly sounds. Basically, all I had was the models and nothing else to make them functioning weapons that also felt good. So rather no mechanics than a bad one.