After feeling his neck being grabbed, the feline quickly whirled around with an arm up to chop him across the Elbow without stopping. If He didn't let go in time, the feline would have broken the arm by pure trained instinct. If he did, then arm would have been slapped away while the cat stepped back.
"Oh! Sorry sir.... but jeeze, your wierd," With that, the cat would quickly break off into a sprint to catch up with the rest.