Pulling a Jan

Suddenly turning around and walking away in the middle of a conversation for no discernible reason. If the dismayed interlocutor asks about it the following day, this is typically followed by answers along the lines of: "Duh! I gave you plenty of nonverbal cues that I didn't want to talk."

Person 1 : I was telling him about the issues I have with the project, but he just walked away! How is that even possible?!
Person 2 : Ah, clearly he pulled a Jan on you!

Person 1 : He said he only had a short question, but then he kept talking for an hour about useless stuff, jumping from subject to subject. I feel completely drained!
Person 2 : Oh well, if he does that again, you should consider pulling a Jan on him.