On the way to work this morning I suddenly realised that for the last few minutes I'd been planning how I might escape from an army of the undead if I became surrounded at that location. Now clearly this is absurd - they'd be far more likely to attack a few streets over where there's a graveyard. That said, you can never be sure with zombies so it's best to be prepared.
So here's the scenario:
There's a large open moor area with cows grazing and a path running across it. You're half way along the path, which by this point is running alongside a 10 foot high brick wall on the other side of which grow a number of large trees at random intervals. It's at this juncture that you notice the undead shambling onto the moor area from all sides - naturally only the boundaries that shambling undead are able to walk through/fall over/tear their way through - everywhere except for the brick wall. Stumbling and dismembered as they are you have a couple of minutes before they converge on you. You've got a laptop in a backpack and a long leather jacket.
What do you do?