Maybe this is a fic prompt. I was just thinking about her line to Gast that goes something like “If I hadn’t met you, I don’t know what I would have done…” and Gast responds with something like, “there, there”. One of the game’s little mysteries. I like that it’s kept mysterious! I suppose an obvious idea is that Shinra had caught her for some experiments, and Gast helped her escape, but I’ve never liked that because it feels too repetitive. Curious about people’s ideas!
Though, my own default interpretation is very unexciting; I normally write her as quite put-together so I think I tend to see it as her just having a bad day.