All There in the Manual: In-Universe. When Donnie spouts random trivia about the ultra-valuable Super Slam Hockey trophy, Raphael asks how he knows so much about it. Donnie mentions that it was all in the free pamphlet.
Disproportionate Retribution: The whole reason why Arboost staged the entire heist was because they wouldn't sell him the Super Slam Hockey Team.
Misplaced Accent: Since Casey Jones is terrible at doing a Southern accent and Donnie is the only other human with them, Donnie does a Southern accent and pretends to be Mr. Slim's nephew. Since Mr. Slim is caucasian while Donatello is Japanese, he claims that he gets his looks from his mother and then insinuates that the receptionist is racist for her assumptions.
Workaholic: In typical Donnie fashion, Donatello represses his mixed emotions over the Invasion and the precarious situation his family is in by working on Metalhead.
Would Hurt a Child: Mr. Arboost and his thugs are not above shooting at Casey, Donnie, Raph and Mikey on multiple occasions.