Some time in the evening she unbolted the door leading into Mademoiselle Cynthia's room. 
Mademoiselle Cynthia's room was unlocked and the door was left open sometime during the night. 
mnli hypothesis: Mademoiselle Cynthia's room was unlocked and the door was left open sometime during the night.  premise: Some time in the evening she unbolted the door leading into Mademoiselle Cynthia's room. 