If John's being honest with himself, he deserves everything he's got coming. He's not sure what possessed him - he hadn't been on a motorbike since the early days in Afghanistan. But when Lestrade showed up on that gorgeous old Triumph, all gleaming chrome and matte black, and then offered, after seeing the look of desire on John's face, he couldn't resist taking her for a short ride.
Thankfully, he'd not been going very fast when the back tire skidded off some fresh paint on the road. He'd managed to land in such a way that the bike suffered no permanent damage, but unfortunately the same couldn't be said for his back. A quick trip to the A&E confirmed a hairline fracture in one of his lumbar vertebrae, and they left with a prescription for painkillers, bed-rest, and a custom-fit orthotic. Inconvenient, but far better than a full-body cast and traction.
Now Sherlock's hovering awkwardly at John's bedside, unused to being the primary caretaker in the flat.
"Do you need... water? Paracetamol?" John smiles as Sherlock worries the cuff of his shirt. "It... it pains me to see you like this, John. It's my job to get hurt and your job to look after me."
"I'll be fine, Sherlock. Thank you." John groans softly, repositioning himself and adjusting the back brace.