One Gonna Heal My Body [now closed]

Feet barely touching the slick streets, Zack burst into a run. A wide grin spreading across his face while rounding a corner so the short building came into his line of sight.
The humid night air stuck to him like plastic wrap but the teen didn't care. After spending twelve hours stuck up inside the Factory, this was bliss.
His shoes slid against the wet road as he stuttered to a stop. The boy's eyes narrowed in on his target, the low roof of a sweet shop. His grin even wider and he posed himself to sprint at the edge that dipped closest to the ground.
Taking in the dank air, Zack touched the tip of his fingers to the path beneath his feet.
Suddenly, he stirred his muscles back awake and dashed to the building.
It was intoxicating, the feel of just letting loose and running without barriers. Jumping, Zack snagged his fingers on the edge of the roof and pulled himself up. Without skipping a beat, he half crawled/ half walked up the pitch of the roof. When he reached the ridge, the teen couldn't hear anything but his heart pumping in his ears. Placing a hand on the ridge, he swung his weight over and let himself slide down the other side and off the roof.
He stopped for only a second before taking off towards a higher building down the lane. He ricocheted off a crate and veered his body onto the edifice's crown. Rolling over, he stood up on the flat roof and continued his journey to the other edge. Zack leaped off the side and discovered there was nothing to cushion his fall, no crates or barrels or anything. It was a dead drop to the concrete below.
In that brief moment of free fall when the realization that when he reached the ground something was going to hurt hit him, the grin was wiped off his mouth and he lost the high that this "adventure" had given him.
Stupid...
On the good side he landed feet first, on the bad side he hit feet first. Sure his head was protected but the jarring motion of contact with such a hard substance sent pain tingling all the way up his spine. Groaning, Zack fell over to his side, rolling his head into something hot and gooey. Slowly reaching up with his hand, he dipped his fingers into the stuff, lifting it up to examine it in the moonlight. Blood. Oh God, was it his? Was he hurt so bad he couldn't even feel it? Panic cut at his heart and his temple was throbbing with a headache at this whole situation.
Trying to wobble up to sit on his knees, something moved in the corner of his eye. Falling over, trying to scoot away from whatever was in this alleyway with him. Some kind of whimper escaped his throat and he kicked himself mentally for making it. You had to be strong, even if you had just dived off a roof and was scared out of your wits.

The warm blood was smeared in his hair and down one cheek. The heat from it was making Zack feel closed in as his heart beat loud enough to wake the dead. The silhouette was closer now and was speaking to him. Zack couldn't hear it. He scraped at the alley wall, trying to find a hold to pull himself to his feet. The brick was cool and he pushed his clean cheek against it trying to calm himself down.
Nice fall A rather deep, rough voice told him. Zack took a deep breath to get his thoughts grounded. When the figure made no attempt to stick a knife in him, Zack slowly pulled himself up, digging his fingers into a crevice in the wall. Wincing, Zack discovered his left ankle refused to hold any weight and leaned against the wall.
Zack dug at his brain trying to figure out something to say. Something... anything!
"I have a knife!" Zack pushed off from the wall and made his legs hold his weight. The pain was almost unbearable but he held firm. Biting his bottom lip so hard the ting of iron reached his tongue.
Too bad he didn't actually have a weapon.