This is well designed. You answer questions the reader might have. Is she safe--yes, she's on the estate. Did the explosion destroy the codex? No, the inside of the safe is untouched.
We understand the motive of the thief, and the motive of the librarian. You create suspense and resolution. We do wonder though, will she have a job tomorrow?
Thank you for posting this suspense-driven story in the Ink Well community.