This is what I think happened in the episode Slash and Destroy while Mikey was following Leo's (Slash's) voice, and Raph was tying up Don's arm. Just some brother fluff and a few swear words (nothing to cussy).
Picking up at Donnie's line...
"Mph! Tastes like leather and sweat!"
"Just stay still, wil ya? Your arm is gonna hurt worse if ya keep squirmin'!" Donnie winced as Raph touched his arm.
"Well, I'm sorry, but right now I kinda want to punch you in the face with my one good arm!"
"PLEASE! Stay still! Let's just start." Raph started, touching Don's wrist.
"Ow, crap," Donnie said as he cringed in pain.
"Sorry! I guess that's where it hurts. Anywhere else?"
"My elbow hurts a bit, and I can barely feel my fingers."
Raph touched Donnie's fingers and Don immediately pulled back yelping, but then cringed in pain at the way his elbow bent.
"Okay, your fingers may be broken, but I'm not sure. Can you bend them?"
"Maybe." Don tried to bend his fingers, which proved to be a mistake, because as soon as he bent them he yelped and started swearing.
"Crap! Stupid little, uhh!"
"Okay, let's test the elbow." Raph touched Don's elbow, but it obviously didn't hurt as much than the rest of his arm, even though he slightly winced. Raph tied up Don's arm and helped him up. As they walked along Don's voice came to Raph's ears.
"Hey Raph?"
"Yeah?"
"Where'd Mikey go?"
"I don't know. Let me go check."
"Hey Raph?"
"Yeah?"
"Stay safe."
"Okay, bro."