The Lost Sanatorium

You are a famous researcher, and you found out that in a very popular sanatorium that thousands of people visit, an accident happened where nobody knows what really happened. Many people say that it was a fire or something. The sanatorium has been abandoned for almost a year, but you want to find out what actually happened. So you go to the mountains and try to find out. Finally, you reach the sanatorium, which is very far from any communication/internet. You experience a lot in your visit, but then suddenly...