User blog comment:Holly Bailey/Thing I Hated About School/@comment-4849011-20170603183040/@comment-25947144-20170603183518

"[Can someone explain how you can "run over" someone who's behind you when you're going forward?]"

Obviously, by warping the space-time continuum. You have to be careful when doing that in crowds, a Doctor like the one you encountered might notice it.