That might make her collapse but it should not make her go rigid the way she does.
Rigidity - I do believe that is a symptom of rabies!! I saw a mad dog once as a kid, I had to drag my little sister out of its way, it was walking all stiff legged! Of course it was walking, but maybe later it got worse.
I watched a different video (than the one most have seen) showing HIllary heading to the van, and I get the impression that whatever her problem is, it causes her to lose her vision.
Thus, the flashlight (that people think is a diazapem pen).
When she is walking to the van, her head it tilted slightly up as if she is not looking at anything in front of her.
The part of the video where she seems to collapse is when she 'blindly' steps off the curb.
And we all have seen and heard about the BLUE glasses.
I put all that together and it says something makes her temporarily blind.
Since I'm not a doctor, I have no clue what medical condition invokes that problem.