You will be talking to Leyland for a while, when Dee comes along. She has 'found' a bag. An argument starts and the some people with torches start shooting at you. Run and follow Leyland and Dee.
you will fall down a bank and head across the road into a cornfield. Keep moving forward, but if you see a torch up ahead, move left or right. Then go forward again. You will eventually come out by a tractor.
There is a metal bar sticking out of the ground. Grab it and be prepared to hit someone coming past the tractor.
*** Spoiler - click to reveal *** It is Dee. You will smash her head in before you know it is her. You cannot avoid this. If you don't hit her, the 'person' with the torch hits you and kills you instead.
Leyland will come out of the corn and talk to you. When you leave, you will get the achievement.
For those having trouble getting the metal bar out of the ground try this solution. Credit goes to SinusNeocon.
*** Spoiler - click to reveal ***I had problems pulling out the rebar from the ground - the onscreen instructional are wrong.
here's what you need to do:
bring the cursor over the rebar, press and hold A.
then push the left stick to the left, then right, then left until bonnie pulls out the rebar from the ground.
don't use X or RT, the both don't work and the sequence breaks.