Patient non-compliance

I am currently on my Cardio placement and am treating (or lack of) 63 year old woman who was admitted due to feeling unwell on a background of idiopathic thrombocytopenic purpure (low platelets and bruises easy for no known reason). My issue is that she refuses all physio treatment. At home she ambulates independently with a WZF but in the hospital most of the time she refuses to get out of bed. Her excuses range from, not feeling up to it, she might fall over, will do so when she is ready. The more I try to educate her on the benefits of ambulating the more aggravated she gets, in fact she screamed at me last week. Her chest at the moment is clear, however I still think it is an important prophylactic to get her up to ensure she doesn’t get any chest infections. I have tried a number of strategies such as education, idle threats (“the Doctors will get really mad at you”), tried to make compromises and even taken an interest in her scrap booking, however all to no avail. I am now tempted to use a cattle prod to put this woman in motion. If anyone should have any ideas of how I can get this woman up and ambulating with her WZF I would love to hear.