Unless you have eyes in the back of your head stepping backward is never a good idea. sideways shuffle maybe, turn sideways and walk where you can see where you are going maybe but facing the threat with both of your feet under you and maintain your balance is the only sure way you can respond effectively. Fist fight, knife fight or gun fight it doesn't make any difference. If you can't take cover and you can't out run the threat then face it.
Life Member of Wisconsin Libertarians, WGO, GOA, JPFO, NRA, American Legion and VFW
Women are pretty but guns, dogs and mules have never lied to me