Author's note: I know that the story does not conform to the original story but I had to write it anyway.
Story starts right after the fight was over.

Chapter 1:

"Steve! You good?" he heard Danny call from somewhere.
Too exhausted to open his eyes, he just waved with one hand.
But actually, nothing was good. He felt like he got hit by a train.
It had been a hell of a fight and the fall or better the impact the worst of it all.

Steve felt like he wouldn't be able to get up – ever again and he hoped Danny would take that long to get to him.
'That is total bs,' he thought to himself. 'That…'
"Steve! Hey, come on Babe. I'm talking to you."
"Just…just give me a minute. You…you can cuff that guy in the meantime," Steve mumbled.
"Already did that. And you already had 5 minutes," Danny answered.
"Impossible. You…you just came here," Steve said.
"No. I came here…about 6 minutes ago and you said you need 5 to get up. So, time is up. Rise and shine."
Steve pried one eye open. "Can I have another 5?"
His voice sounded strenuous and Danny got really worried.
"Did you hit your head? Did you break anything"
"Hit everything…don't know about breaks." He closed his eyes again.
"Steve?" Danny asked another time.
"Don't worry. Just checking" came the reply.

"How about I'm calling an ambulance and the EMTs do the check?"
"No. 's not necessary. I'm good. Just give me…a hand."
Steve held his hand out.
Danny looked at his friend and when Steve asked "What are you waiting for?" Danny took it.
He pulled Steve up who helped as best as he could but when he was upright, he said "ow" and bent down again putting his hands on his knees.
"You okay?" Danny asked another time.
Steve just blew once before he stood up again with a low groan.
"You good?" Danny asked once more.
"Yeah, yeah. Never better" Steve replied and started walking.

That was at least what he wanted.
But he could only limp and the first ten steps were accompanied by a hiss.
Danny watched him from behind but didn't say anything until they had reached the front door and Steve tried to open it.
He reached for the handle then he hissed another time.
Instead, of opening the door he put his hand on the wall and hissed again. Then he groaned and put his other arm protectively around his right side.
He closed his eyes and tried to breathe deeply.
Another groan escaped and he tried with shallow breaths.
Despite the concern about Steve Danny couldn't help to say sarcastically from beside his friend "I am fine, huh?"
"Didn't…say…that," Steve retorted. "And I…just made…a wrong move. Just give me…a minute."

'Much better,' he thought. 'Should have known.'
He took a few more breaths and opened the door – with his left hand.

Danny just shook his head.

After a short briefing with the rest of the participating team members and the arriving HPD officers, Steve limped to the car.
He opened the passenger side took the key out of his pocket and threw it on the driver's seat.
"You are driving," he told Danny.
'Mus be bad,' the addressed thought but scoffingly said "Very nice. Thank you."
He rounded the car took the keys and sat down.
Steve needed some more time.
When he was finally in, he closed his eyes and put his left arm around his ribs again.
It was obvious to Danny that his friend was in a lot of pain.
He waited until the latter had regained his composure.

It took two long minutes which felt like a lot more to Danny.
Then Steve opened his eyes. He looked outside then turned to Danny.
"Why aren't we driving?"
"Maybe I forgot how to do it because you are always driving my car," Danny replied ironically.
"That's bs. You are driving to work every day…or to my house to pick me up."
"True."
"Then why aren't you driving? If you don't want to drive, I…"
"No!" Danny interrupted. "You are not going to drive. But you are not buckled up."
"No need. You are driving." Steve smiled.
"Funny," Danny commented. "Buckle up," he added.
"Don't…" Steve started.
"Buckle up!" Danny repeated a little louder.

A whole minute went by until it was done.
Not because Steve had argued against it another time but because it had taken him so long to finish the task.

He had tried to grab the seatbelt with his right hand to avoid turning himself but the pain that had shot through his shoulder had made him stop immediately.
So, he turned to use his left hand.
That had hurt even more but he knew Danny was watching him. If he'd stop his movements again, Danny would notice that something was wrong.
'Who am I kidding,' Steve thought. 'He knows anyway.'

When Steve was done, he looked at Danny and asked "Happy?"
"Yes, I am," Danny replied. He started the car and drove off.

Steve closed his eyes and tried to ride out the pain that got worse and worse.
The bumps in the road didn't make it better either. He just wanted to lie down somewhere and sleep – nothing more.
He could feel Danny's gaze on him but decided not to react to it.

"You know," Danny said after almost ten minutes of driving "now that I'm driving, I can decide where we are going, right?
I mean the driver the driver has the control and all."
Steve didn't respond.
Danny nudged his friend's shoulder.
"Hey! Steve? You heard me?"
"Yeah. Just drive." Steve sounded sleepy and exhausted.
"Okay," Danny said. I decide and I decided we are going to the hospital."
"Okay."
"I said we are going to the hospital. Getting you checked over," Danny repeated.
"Heard you. And I said 's okay," Steve mumbled.
Then he fell asleep.

"Hey, Steve," Danny said softly and carefully nudged his shoulder "Come on wake up."
He got a low moan in response but nothing else.
"Hey, come one," Danny said a little louder.
"'anny?" Steve asked blinking his eyes. "Ow", he added when he moved.
"I am sorry Steve. But we are at the hospital. I thought you'd like to go in alone."
"Why? You…can't see blood?" Steve mumbled.
Danny sighed.
"I meant on your own two feet. Of course, I am going with you. Even if it is to make sure you don't tell the doctors that you are fine.
"But…I'm…just tired."
"Sure you are," Danny replied. "Like you said earlier "Never better"", he added.
"N…never…sssaid…that."
"Steve?" Danny asked concerned.
"Huh?"
"Would you mind getting out of the car or do I need to get a doctor or a nurse out here to come get you?"
"No. 'm coming. 'f…'f I can sleep then."
"Yes, you can."
"G…d."

It took Steve even longer to get out of the car than he had needed to get in.
Danny had thought about telling his friend to stay in, that he would get someone to get him but he was afraid that Steve would come out anyway when he was alone. He didn't trust his partner to know what was really going on at the moment and therefore not to stay in the car if Danny would tell him that.

"Sir, you can't park here. This place is reserved for incoming ambulances," a male nurse who had come out of the hospital said.
"I am not parking," Danny told him turning around. I am Five-0 and I have a patient in here."
"Yup, I guess so," the man answered wide eyed.
Danny turned around once more.

Steve was standing behind him, grabbing the door of the Camaro, holding on to it like it was his lifeline.
He was pale like a sheet, sweat had built on his forehead.

"'m sick," he brought out before vomiting on the floor.
His legs buckled and he lost the grip on the door. He sat down on the floor, missing the roof of the Camaro by an inch.

"I need help," Danny said turning another time but the man he had been talking to was already inside calling for a doctor and grabbing a wheeled stretcher.

PS: Appreciate your thoughts.