Pull a kuragi
Completely give up on helping your apprentice or friend in game or real life for no reason. Basically just saying you wont help and not caring about it.
Guy: I hope you won't pull a kuragi on me
Guy 2: No I would never give up on you
Guy 2: Gives up and doesn't help
Guy 2: No I would never give up on you
Guy 2: Gives up and doesn't help