I struggle so much with safety... Uncertainty exists, and we won't be able to get rid of that ever, and it increases as we take greater risks with the hopes of building more fulfilling, interesting lives. The greatest tools against the uncertainty crisis is education... learn everything you can about where she is going and the risks involved. Maybe she and you would feel safer if she enrolls in a self defense class? That was something I went towards after my rape. It made me realize, wholly realize, that I am small and physically weak and someone can hurt me and I can't do shit about it. Lifting weights made me feel like I could have more control over my body... Your concerns are valid, more than that, they are loving. Talk to her. She might be afraid too. She might have a million thoughts on this she'd like to work out with you. There isn't a right or wrong answer here.
So one story my therapist relayed to me, which has a history in Native American folklore, related to this is: A scorpion asks a frog for a lift across the river. The frog is hesitant, "Are you going to sting me?" "No, I will not." "You're really not going to sting me?" "No, I swear, I just want a ride across." "Alright, hop on." Right at the bank, the scorpion stings the frog. The frog, as it dies asks, "Why?" "Because I'm a scorpion." I hate this friggen story because it seems like the frog should stop being who he is. Trusting, helpful, self-sacrificing. The fucking scorpion should be the one to change. I promised myself to never stop being a frog out of fear of scorpions. I don't want uncertainty to dictate me life, and it is a constant battle. Constant. Your girlfriend sounds incredibly brave and strong, and resilient as hell. I bet you love her for these qualities. So support her in her fight to keep those aspects of herself alive...
I don't know, that's my two cents. Your situation is complicated, but there's a lot of love and strength in there, and that gives it tremendous hope. She sounds like a survivor to me, as do you. Talk to each other.