That is a very good point, many times during seizures, especially if it persists for >1 minute, a persons respiratory drive will be effected. In their postictal state they cannot compensate, so the assisted ventilation can help. But do not risk bodily fluid contamination over it, that should be stressed. I doubt you will have a pocket mask lying around, so if its someone you don't know and they might be bleeding from the mouth, don't risk getting hep b or c or something. You can try to sit them up and that alone will help them breath.
I actually watched a lady actively seize for around 45 seconds a few days ago. She had already had at least one seizure shortly before that, maybe more but her daughter was only spanish speaking so the most we could get was she was figuring she said something about her being epileptic. Even though she was prone to seizures, it is never good when they are happening in succession like that. To illustrate how it effects the respiratory, I'll note that her O2 saturation level was in the mid 80s% following the seizure and didn't return to above 90% until a few minutes later and with supplemental oxygen.
