I find it almost impossible to understand the sentence after reading it perhaps a dozen times. It is a horrible sentence. The first comma should be after "and" rather than before "and". The final phrase "for obvious reasons..." should be a sentence on its own. ...I think. Really, I'm not sure. The verb "had" desperately wants to have a subject, and the only possible subject , "she", is so far away that the listener can only puzzle over what it might be. If the subject is "she", then "she" needs to be repeated: "SHE had subsequently been swept away". Being charitable to the author, you could say the sentence has the meaning you suggest. But truthfully, the sentence does not merit your time or consideration.

You’ve understood it well. This would be clear in speech but hasn’t been converted to writing correctly. To do that, ‘For obvious reasons’ should be the start of a new sentence’. Being able to understand things with minor errors is a skill that native speakers acquire over years of using a language. Congratulations!

Yes!

My pleasure