…of shabby girls school

i watched a movie in 91-95 about a group of girls living in i want to say a bomb shelter is the only way to describe it or a shabby gray school i remember the room being plain and gray but it had a bunch of shabby beds for the girls staying there, i know they were surrounded by towers possibly even a runway i know the lady who was in charge was kinda fat and really scary (to my 4 year old self) i know at the end of the movie one of the girls runs away and climbs up a radio toweror whatevers outside and the big lady chases her but falls to her death i know its not much to go on but this question has boggled my mind since i was about 5 years old im now 30 any suggestions would be great i want to say i watched this on hbo back in the day for some reason tho i could be wrong