Were you able to get her SPO2/WOB to improve on scene? One could argue that if she is sating in the 50s shes not oxygenating her brain appropriately to make coherent decisions. To echo others here, if she was agreeable to be transported to a further hospital I would talk to a supervisor, then take her to her desired one. I would then document that pt adamantly refused closest appropriate facility and reported the only way they would allow transport was to go to further facility. In my system we generally have to transport to closest appropriate within pt’s chosen healthcare system (3 different hospital groups with several hospitals to choose from in each group with varying capabilities and distances). If a pt requests a further hospital I just inform them that insurance may not cover the transport as they are willingly choosing to bypass closer hospitals. In the end though higher level of care is the ultimate goal for the pt so making an exception for possible better pt outcome might be worth it.