A woman trapped for 30 hours in a locked room in China was rescued after she threw a pillow out the window with a message written in her own blood, according to a statement by the local government.

The woman, identified only by her surname, Zhu, was cleaning a guesthouse in Sichuan Province, western China, when she entered a room without her phone, according to a social media post by the Leshan city authorities in mid-August.

The door could not be opened from the inside due to a faulty lock. Once inside, Zhu was trapped without food or access to a bathroom on the sixth floor of the building.

After a day and a half and many failed escape attempts, “in desperation, she bit her finger and used her blood to write ‘110625’ on a pillow, which she threw out the window,” the local government reported. The number “625” corresponds to the room where Zhu was trapped, while “110” is China’s emergency number.

A food delivery worker, Zhang Kun, spotted the message and immediately called the police.

“I was scared, but when I saw the number ‘110’ on the pillow, I realized it might be a cry for help,” Zhang said.

The police then forced open the door, freeing Zhu. Videos released by local media show her disheveled, thanking the officers.

“I went there yesterday morning, and a full day and night has passed,” the woman says in the video.

Zhang, the delivery worker, received 3,000 yuan (€361) from the Leshan authorities for his role in the rescue.