
I have a glitch in my copy of San Andreas where the entrance to Smoke's Crack Palace is bugged out and instead takes me to Blue Hell. I had recently been curious about the Desert Building, so I did the ROCKETMAN cheat and flew from the Crack Palace to the building. Well, when I went up the cliff a little bit, I was shocked to see that there was a solid floor inside the Desert Building.
I don't think there is an actual way that this can be used in game, unless there is some kind of event that opens the front door. What I think is that this is something from beta, or just a plot line involving the Epsilon Program, that was scrapped; and the devs thought it would just be easier to close off the area instead of reworking the building.