I am curious to know how long she waited a the curb. Was it a very long walk? You would think the van is positioned pretty darn close and would only need a moments notice for a pick up area.
The articles said it was a 2-3 minute wait because the motorcade had to get there. They were not expecting her at that time, she was way early. Medical emergencies can cause unexpected changes. It was not a small one she could sit through and recover from, like prior events have been.