Not a medic or a scientist but I'll try and make this credible. Please prepare for your suspension of disbelief.
Justin blinked and uncurled a bit, his bleary eyes still struggling to focus on Luther beside him.
"I'm listening, Boss." The voice trailed a bit as he screwed his face up in discomfort and winced inwards.
John took a moment to regain his composure and angled the torch further to highlight the small frame and dirty wraps. He tapped Justin's small hand clutching the blanket, enough to get his attention back. John dropped his voice to a softer, coaxing tone.
"Right, I know you're cold but I need to shift the blanket and check for injuries. Any sudden pain, any time you want me to stop, you tell me."
Going by the blood-stained blanket, the large gash on the forehead and woozy expression, he knew there was definitely a concussion but his glimpse under the blanket had promised further injuries. There was a ragged hmm from Justin and his grip loosened slightly.
Gently moving the blanket back, Luther got a good look at the boy's bruises. The kid really was a tetchy thing, swamped even in the few clothes he had on and shivering in the cool wind. He had the lanky look of a growing child but the dark, giant hand-shaped bruises wrapped around his shoulders and arms dwarfed his small frame.
Justin was crumpled up on his right side in a pseudo-foetal position, with his left arm sprawled behind his back so the forearm was trapped between his body and the wall, scrapping against the rough brickwork. The forearm looked discoloured and the angle promised a least a fracture but, amazingly, Justin didn't give a peep as John nudged it accidentally.
Searching with his fingertips, and ignoring the small whimpers, Luther lifted the fabric of the singlet and delicately felt the torso underneath for any deeper injuries, his hand slowing as he noticed some darker bruising and swelling on his elevated left side.
There was a pained cough and his body twitched back as the kid moved to sit up again.
" Justin, Justin, stop!" John caught him as he threatened to fall against his left arm. Re-wrapping the blanket around him to cushion the concrete, Luther shrugged off his jacket and draped that over the cold bundle. Justin was emerging out of his shocked daze and the pain would hit him soon. And the boy's resemblance to Ripley was becoming more obvious...
"Boss, please, something's wrong, what's wrong with my voice, what happened?" Justin twisted his head around to see Luther. "Boss, what is it?!"
"I need you to keep calm, Justin, and answer some questions. Can you do that for me?" He had fallen back into the voice he used on victims, he knew it, but the kid took a breath and inclined his head.
"Right, Justin, how old are you?"
"Thirty-three."
"And how did we meet?"
"Volunteered. The...the case. With the girl, the Morgan shooting."
"Right, Justin, another question: do you know how you got here?"
A small pause and his forehead furrowed. "I-I don't remember, Boss, sorry. We finished up the case, arsonist Walter Benson, and then... And then...what day is it, sir?"
Luther cupped Justin's head as he carefully shone light to check his pupils' reactions. "Doing well, Justin, doing well! The case wrapped up yesterday, on Thursday. It's Friday night now, so just a day to go. Do you remember anything else, the smallest thing?" Ghosting over the bloody gash on the forehead, Luther checked the back of his head for bumps and gathered the back of the blanket just enough to form a small pillow as he lowered his head back down.
"Not really, Boss, sorry. I can't remember much at all. I-I think I left to head home. I had my keys in my hand, and then... John, please, what's wrong with me?" Justin's voice struggled to remain calm now, as Luther struggled to think of the right response. His voice rose in pitch as he wriggled, freezing with a gasp of pain and panic at the sight of his small right hand in front of him.
At a loss of what to do, John reached out and lifted Justin and the sodden blanket to be cradled in his lap, pushing Justin's head up against his shoulder as he began to whimper. Shushing him softly, John carefully supported the boy's left side and adjusted his coat to shelter them both from the cold. The raised hand began to shake violently as the blanket slipped down to show more of his scraped, bruised body.
He hadn't the foggiest what to do to make it better. He sat there, leaning his weight against the wall, as Justin worked his way through his panic and Luther tried to reason what to do next.
Justin had quietened down and an awkward silence had fallen between them.
"Boss, John. Just – what are we going to do?"
Loosening his grip, Luther looked down at Justin and sighed. "Justin, do you have any idea how you got here, like this? 'Cause I'm at a loss."
Ripley shut his eyes and shook his head. His voice caught in his throat as he replies, "No, Boss. No idea."
"Right, well, we can't stay here forever. You need that arm looked at properly, probably some stitches for that cut at the very least, before we do much else. But we're going to have to sort this out." He nudged the kid to get his attention. "Justin, I'm gonna move us to the car now. You alright to stand up? "
Justin took a breath and nodded. Straightening himself, Luther pushed himself up against the wall as he lowered Justin's legs beside him, taking pains to steady the kid and adjust the blanket and coat around his shoulders. The boy hissed through his teeth as the blood flowed down to his legs and woke his bruised nerves. He jolted his left arm, snatching it back up and cradling it to his chest as Luther gave him another searching glance. The breathing was shallow and posture was a bit too hunched over at the waist to calm his worries.
"Mate, you good? The car is not far, but far enough."
"Yea, Boss," gasp, "I'm good."
"Okay. Right." Standing up straight and scanning the car-park, John hunted for any sign of movement in the shadows or periphery. It must have been nearing midnight but the photo proved someone knew Ripley was here. Seeing nothing, he rested his hand on Justin's shoulder and nudged him in the direction of the exit. "C'mon, let's get out of here."
They took a few slow steps across the allotment, Justin limping slightly as he favoured his left side and tender soles, until John couldn't take it much longer and carefully scooped the boy back into his arms. Despite Justin's initial squeak of protest and short struggle, they reached the car quickly and, with Justin bundled in the back, Luther drove away.