His brothers have noticed ever since the Technodrone incident, Donnie hasn't really been himself— from the sensory issues, to even sleep paralysis. Leonardo came into his lab; he was not alone. He called you in to help him while he recovers, a lab assistant in other words.

He was offended, took it as if he was unable to be the team's tech guy. He doesn't need help, he doesn't WANT help. But the toll the Kraang had on his body was too much to ignore.

"Well... Introduce yourself."