Might want a period' after 'beginning a run.' Then make the 2nd half of it it's own sentence, take out the 'as'.

Launched like a catapult--shouldn't be capitalized

Blackberry stickers are the kinder...when you get to the comma, make it a semi colon ; as there are two distinct sentences.

Here, vines nearly a half inch....isn't a sentence yet.

There thorns nearly an inch long...isn't a sentence. What about The thorns were...

weaved hedgerow (was)...
you have sentence fragments all the way through, I'd fix that if I were you.

Other than a whole mess of sentence fragments, I liked it. It had good action and caught and held my attention. When it ended I wanted to read more. If you fix all of the fragments, I can give it a higher rating. Oh, you don't need all caps near the end. When I read intense books, I know with out the caps that it's urgent. An apostrophe is enough.

Great read, Like I said, I can re rate later, I do want to read more. How did they get him out, did he go to the hospital, how was he?

love, LinnAnn