I'm not sure what the writers intended, but I think logically there is a fair chance that Fabiana survived. Balen left the key as a clue, which is more than Fabiana had to work with. But more importantly, what would the police think upon finding out that TWO girlfriends had vanished from this guy's house? They'd tear the place apart.
shareYeah, I know this is an old comment, but I definitely think that Belen would have to show up eventually and that would save Fabiana's life.
Remember, Belen is from Spain, she's not native to Colombia, so she's not going to want to be homeless there with no money, no job, no friends, no nothing, so in order to get back home, she'd have to reveal herself. Once she does that, then they know Adrian's innocent and Fabiana's locked in the panic room