Hi, Glad it worked out OK - good advert for having a (competent) buddy.
A few thoughts, you mentioned your symptom of diaphragm contractions - what did it feel like exactly, did it interfere with your breathing? If this wasn't diaphragm contraction but palpitations (can feel like fairly dramatic thuds in the chest too) then it could have been an abnormal heart rhythm, which could possibly be caused by the aerius (listed as a side effect), and may be made more likely by the scopolamine (also increases heart rate). The seizure would then be secondary to a lack of blood to the brain - we see this occasionally in hospital, when people lose their cardiac output they can have a secondary seizure.