Old dude walks onto the train. Like super old dude. Maybe a Kung fu master type of old. He's a regular troublemaker. When we see him, we know that he's going to harass someone. Everyone knows a public commuter like that.
So, Dude is humming a tune but as he passes the first person, he says "Duck" and touches the top of their head. "Tap". It's gross. He continues in a predictable manner as everyone tries to dodge his awful hand. "Duck 'Tap', duck 'tap', duck 'tap', duck 'tap', duck 'tap'," he repeats this mantra as he touches scalps. He touches your head and you feel microbes leave his finger tips and invade your head.
So things are getting intense because no one knows what's going to happen when he reaches the back of the train since there's this big guy sitting at the end of the train with a I-wish-you-would expression on his face and Bruce Lee's master is in the middle of the coach already. It's like Russian Roulette after the trigger's been pulled for the fourth time.
Anyway, touchy dude is busy ducking all the passengers and time's finally up. The big guy, who's probably about 55, is confronted by the super ancient dude. It's awkward and intense and a stare off is underway. Now, I already got my frontal lobe blessed by this guy, so I'm waiting for the big guy to get his.
The old guy raises his hand like a priest. The word that we anticipate is about to come out, he gets the first syllable out, "GOO..." and WACK!!!! The big guy strikes him with the power of Shaka Zulu. Everyone erupts. The old man falls, stumbles up and leaves the coach, never to be seen on the train again.