Why didn't the british woman escape?

she had a head start but he knew the area, may have even planted some traps ahead of time. also he may have threatened to shoot her or have actually done so (non-fatally obviously since we see her captive and killed later)

~~~
"I don't care, I'm still free. You can't take the sky from me..."

That scene was a bit confusing, because it was hard to tell what was going on after he gets out of the car. You hear her screaming, and then suddenly, he wades across the screen, and stands in front of those bushes.

He opened the front door, but she was in the back seat. There was wiring between the front and back, like a police car, so she couldn't climb into the front seat. He had removed the handles so the back doors couldn't be opened from the inside; she was basically in a cage.

He opened his door in the front, but he did not open the back door, where the British woman was sitting. He also took the handles off the back doors. She couldn't escape.