You could always accept the offer for now to calm things down at home. Then give it a good think over the next few weeks and if you still feel the same way you can change. On another note if your parents really are serious about throwing you out just for not doing the subject they want that's pretty serious. Phone Childline or some other similar charity, they will be able to give you much better advice on what to do.
I'm shocked that there are parents like that on this planet :| no offense to your parents but like in the end it is your life kicking you out is way extreme.
Work with BMJ. Best of both worlds baby.
They'll see reason in a few days (or even hours). If they kick you out, they'll realise what a terrible mistake they made.
Accept it then switch when you get there or accept it change during clearing and tell your parents your going to do medicine and then get some student accomm which is 52 weeks
If your parents want the best for you so much that they push you into medicine and then they shout at you when you don't want to do it, then I'm sure they care about you enough not to throw you out onto the street to become a tramp. They are majorly bluffing.
Wish I'd gotten that option really since medicine is what I want to do and I haven't had any offers.
However, it's your decision and you shouldn't go on to do something you don't want to do. Your parents should appreciate that.