She may have had a 90 day Visa but how long has she been in Spain prior to entering this apartment. That no one really knows.
Or she had a better business opportunity arrive and she can't turn it down. Or when she signed the contract for entering the apartment could have only been for a month.
This apartment is known for girls coming and going whether it be for 1,2 or 3 months. As soon as Layla entered the apartment it was a given that someone was going to leave.
Wherever she goes and what she does I wish her all the best in the next chapter of her life.