Her face didn’t actually hit the pavement this time. That makes it “near” collapse. If anyone else gets woozy in public it is a “collapse.”
If the Secret Service hadn't been there to catch her, she would have powered through the sidewalk face first.
I guess you are right. They know she will collapse at anytime, so she has people around her, ready to catch her.
The first time I had a seizure, I fell like a tree into asphalt. I assume she had that happen to.