Nope Trump should stay behind his podium, after she fall flat on her face, he can be a gentleman and walk over and help her up. But don’t try to prevent it, it can only harm Trump. It would look creepy to people watching.
Just like when Al Gore walked up to George W in one of the debates, that was creepy as well.
If Hillary collapses wonder what the Vegas odds are, then Trump just stands there and let her handlers pick up the cadaver.