Firstly, congratulations on your new family member!
My girl Sophie has partial seizures. They started after a head injury when she was 3 and she's now 9. Some of what you describe with Fey sounds similar. Sophie's seizures seem to affect several of her senses, so the behaviour she exhibits during a seizure can vary, from appearing afraid of the ceiling, or fly-biting, or gum-chewing, or nibbling her skin as if she has unusual sensations, or sometimes it appears that she can smell an unusual smell. One thing is always present, though, and that is fear. Sophie is fully aware during these episodes so I can interact with her and can sometimes stop the seizure by taking her for a walk round the garden or giving her some food.
I also have valium from my vet - 10mg will stop seizure activity in Sophie in about 20 minutes. I would not want to be without this and would suggest you consider asking your vet if you can have some in case it happens again.
Videotaping an episode is very good advice, as is the suggestion to keep a detailed log. Through doing this, I discovered two things that triggered seizures in Sophie: Frontline spot-on and Thuja. I've never identifed stress as a trigger for Sophie, but triggers are likely different for each dog.
Sophie used to have these seizures every couple of weeks, but they have gradually got less frequent. I just checked my log and it's been almost 10 months since her last seizure, which is the longest she's been seizure-free (excuse me for a moment whilst I do a small celebration dance! ) So now I'm wondering if the fact that I've been detoxing my house over the last few months ie gradually changing over to toxin-free household cleaners and toiletries etc has something to do with this.
Anyway, I think your vet is right to say to not worry about it just yet, as it may never happen again. In the meantime, just be aware, start a log and enjoy your new girl.