I have only played zombies since getting the game and have come to find that when running a rape train its very easy to get cornered but what I have found is that if you just keep jumping you get a extra 10 seconds or so to get out of the corner before any zombies even hit you?
Occasionally sometimes where your jumping the zombies throw you up above them and you can run out, or possibly even get onto a Barrie I myself have never done this but is possible I guess lol anyway take what you want from this hope it helps in some way

-LooSe