How do you push the walker off in the PC game?

[Joshua1991]

I'm on my second walkthrough where I saved Doug in Ep 1 and in Ep 2 I'm fighting off the Walker in the Moter Inn in the beginning and I was wondering in the PC version of the game how do you push it off so Mark can kill it?

[pdlbean]

move your mouse to the right when Mark tells you to move so he doesn't hit you