Mello shrugged "I'd kill you if you had been able to meddle in Fujiko." Mello closed the book and put it back, looking at her "You are too noisy sometimes, and you forget with whom you are messing." Mello allowed Fujiko to joke around, he even found some amusement with all that poison and virus thing; but when it came to Mello's plans, he'd kill anyone that tried to interfere.