Facelift Game - Vol. 1 Ch. 16

[MangaDex]

 

[BuyVelomobiles]

I don't see why she couldn't just say "Don't play with that. It's for your parents" or something. The task was to throw the lighter, not let the kid burn the place down. If she was worried about the task failing her for stopping what come after (Which would be new behavior), she could literally stare the kid down, then ask for it back after the task finishes.