This artwork started following me

Went to the Hayward Gallery to see New Art from China. Photographed what I thought was a very realistic waxwork figure. Then read the explanation beside it. It said this was a performance piece about surveillance where the observer becomes observed. The figure dressed as a mental patient picks a visitor and then follows them throughout the exhibition. Sure enough as I walked away she followed me. Amusing at first, it was also somewhat unsettling. She always contrived to be behind me. If I went into a corner and turned around then she just stood and stared at me until I moved on, then she got behind me again. Eventually I came to an installation piece where you had to crawl through a low doorway to enter a structure. I crawled in but she did not follow me. Later some other people came in who were discussing the strange woman in pyjamas who was stood waiting by the entrance. I explained what was going on and everyone started giggling and no one wanted to go outside. Eventually a woman came up to me and said, "She's just gone". I went outside and did not see her again. Now that's what I call art.