While at the first it may seem nothing, I noticed one map thumbnails it shows it next to a city named Bagdad, Very strange to me. I trying to make sense of if a real facility exists, this leads me to believe such does. Since there are 10 different possible locations I believe the BMRF is massive and has many above ground entrances located throughout the town of Black Mesa and other surrounding towns, Bagdad one and that like in HL it is mainly underground.