Why not make friends with the cab driver? The scene looks like it's set up to capitalise on the humour of having the freakazoid character interacting with a straight-laced sort of guy who seems remarkably unfazed by him. As if this is an everyday occurrence in his cab. Being in the back is lonely, so inevitably, he sorts that out to sit next to his new friend. As Miller says, he can't help it:
"Hes like a kid with ADD whos had too much sugar and he cant sit still - hes constantly fidgeting and looking to entertain himself. Im sure theres a word for it that therapists have for those kids who need constant input! But hes definitely that guy. He needs to talk. Hes a fidget."