Mm this happens often on the tube though. As much as you can sympathise with her, try to sympathise with the other ladies. Imagine working a long shift, been on Ur feet all day, have to stay on the tube for 45+ min to get home, all the seats are taken and this girl won't let u sit in the only empty seat? Some people are just arseholes who think their property is more important than another human, and I think with her fake posh accent these ladies assumed she was being an entitled cow, although I agree with you as an observer there are clear traits which indicate some sort of mental issues. Like I said Ive seen (and had) these arguments before, it can be really infuriating when someone is denying others the opportunity to sit down (i assume they asked her if they could sit there initially, rather than jumping straight to an argument). If you can see her side then you should try to see theirs as well.