My 12 year old Sister Wants Revenge on her Doctor Who Wont Give Her Liposuction!?

My 14 year old sister recently decided she wants to become a runway model in Los Angeles and gain international acclaim for her slender figure. She is already contemplating a relocation as early as next year. I believe in her choice and think such an occupation is lucrative and desirable. She has the height for it, the looks, the mindset and a wonderful figure. However, she does not believe she is skinny enough to seriously compete with other models. She is now dead set on getting liposuction in order to lose the weight necessary to enhance her career prospects. I see such a surgery as a strategic career move and support her decision. Last week she saw a doctor who refused to give her the operation because he claimed it was not necessary. She is enraged that this doctor will not give her treatment and is now plotting malicious revenge. She wants to go beat him up with a private collection of whips and chains she has on loan from her drug dealer and then burn down his practice with kerosene she bought from her friend on myspace. I have told her it is not worth it and that she could get into a lot of trouble for such a crime but she has told me to shut up, mind my own business, or risk getting beaten myself. I took a stand for myself and announced that she cannot boss me around. She then threw me into our computer office and has locked the door so I cannot get out! She already borrowed her boyfriend’s car, loaded it up with the whips and chains and plans on being at the doctors office first thing tomorrow. How can I stop her?