Brimley has not had any more seizures. I think it was hypothermia as I didn't wrap him up as much for the cold as I usually do because I didn't think it was that cold out. All but one of his seizures happened when he was exposed to the outdoors. Yes, I'm an idiot and it will definitely not happen again. I still don't know exactly why he had a seizure in the vet's office, but the vet thinks it was anxiety from the visit even though he has been going to the vet twice a year for 12 years and has never had anxiety before. Of course, there were a lot more birds making noise in the waiting room this time and that may have freaked him out a little.