That door (facing west) has never been opened. It is said that a professor will die if you open it. Whether it's superstition or feng shui, it's just not open now, only the door facing south.
There are many interesting supernatural stories in the South Campus. You can get a lot from searching the ghost stories of Sun Yat-sen University on the Internet.
However, there is no official basis for these, and they are all hearsay.