Bolt past!

You attempt your tried-and-true tactic of "running past them" once more. With a push-off from the wall, you sprint down the stairs, all the while gathering momentum. Your trajectory is fully planned, every step you're going to take routed in your head. You're going to make it! The wind rushes through your head as shoe meets concrete and you swing your arms right to give you the inertia to dodge past the zombie's groping hands. And then your left shoe, being a sensible black flat shoe for office wear, slips off. You slip. You tumble. You crash to the ground.