Tactical L retreat , adds lateral distance as well, not straight backpedal, but still a losing propostion. Do the best you can if you can't get a barrier between you. And, to agree totally with the above; get mentally engaged really early into the "hey, got a cigarette" scenario or somebody walking up on you while pumping gas. You'll never beat a blade or impact weapon at arms range; you've got to have the room to recognize, react, and execute an action ( three very different steps). Action will always beat reaction, every single time.