wrong diagnosis

Third week of my neuro placement. A patient was admitted for a ? TIA due to increasing weakenss in the legs and 3 falls in a week due to her legs 'collapsing on her'. I did a full neuro assessment on the patient and she doesn't have any unilateral motor deficits or any neuro deficits. She has bilateral weakness in her LL (gr4). I assessed her functional tasks and she required maximal assistance to sit to stand (and could only stand for 5 secs before sitting down again). She gets very SOB on attempting to stand. She also desaturated to 82 just with attempts to stand. Her SpO2 in the morning was 88. I got the nurse and she put the patient on O2. I decided to stop my assessment there. I talked to the patients husband and according to him, the patient has been very inactive for weeks and she requires assistance going in and out of bed at night and could only manage walking short distances within home (i.e. bedroom to the lounge). I told my supervisor my findings and I told her that it couldn't be TIA because the patient has had the legs weakness for weeks and TIA usually resolves within 24 hours and the fact that she desaturates with attempts to stand, that suggests some other pathology that could be happening at the same time. Next day, I tried to see the patient again but the nurses told me that she had a MET call. She was transferred to another hospital that evening due to a large PR bleed. The patient also has a very long list of PMH which includes Cancer and therefore her current presentation might have been an exacerbation of her previous conditions. The fact that she is being diagnosed with a ?TIA doesn't really justify the signs and symptoms that she presents with. From this experience, I have learnt to just not to accept any uncomfirmed diagnosis and to go with the signs and symptoms that the patient presents with.