PSMKay, I have to disagree. Expulsion only teaches this student that her ex still holds an extraordinary degree of control, and that even adults in a position to protect her will cede authority to him instead of support her.
I'm glad to hear jess1532 is working with the director, and that the director is, in turn, collaborating with school officials (admin, campus security...?) to find a solution. My next question, for the group at large, is WHAT ABOUT THE PARENTS?
This young woman is still, legally, a child. Without knowing the particulars of the neighborhood, the school, the unique details of the summer drama program, I'm very curious why this student doesn't have a parent or guardian picking her up, or, in fact, mentioned anywhere in this thread. (jess1532, this is clearly sensitive - I don't, nor does the general public need, to have these details about your situation!)
In my view, if the SM and ASM are the people helping this student through a scary, scary situation, they should be kept thoroughly informed of the steps taken by the school, director, parents/guardians, and any other people involved. They (and the rest of the adults) should also have a picture of the ex, so they can spot him if he is indeed hanging around the campus.
Expulsion is the absolute last thing that should happen. All it would accomplish would be to sever the already-tenuous lifeline this kid has to adults who can supervise and teach her this summer, and, hopefully, provide a healthy model for how to handle a terrible experience safely and with grace.