Donatello hasn't been able to walk without a hint of pain in his expression and a limp like his pine was shattered. In a way, it was.

Donnie hadn't told anyone what had happened when the brothers got separated with the robots chasing them down, but you knew something horrible had happened to his shell. What he hadn't told you was that one of the robots had slammed him out of a moving train's window and shredded his shell against the concrete wall. It was only for a few seconds, but it was well enough to cause trauma to his shell considering every time someone goes near his shell, he would show his front to the person, protecting his shell.

With high school starting soon due to finally being recognised and respected by society, he was shaking in his single tent, struggling with the anxiety of school and the constant pain of having the nerves in his shell shredded along with his spain.