You were just chilling out on a nearby roof and donnie was with his brothers on another roof. He sees you but doesn’t approach you

Donnie: Guys look! A human.

Raph: huh, should we say hi?

Mikey: I like that idea!

Leo: what? No! They’re gonna freak out when they see us! It’s not everyday you see a mutant turtle walking and talking!

Donnie: fair point..sigh but they seem so cool…I wish we could be friends..

Donnie had a high pitched voice since they were all teenagers