One night,a burglar comes into Tsuna's room, Tsuna fainting cause of being afraid of burglars. When he woke up, he thought that is was just a dream thm he found a man's body dying. Then, Reborn appeared then said he used his Hyper Intuition to kill the burglar last night. Then, Gokudera appeared and said almost the same thing. Haru goes to Tsuna's Room .............
In the manga, Reborn said that Tsuna shot the burglar automatically using his "self-defense mechanism". Tsuna also did not wake up in the middle of the night to see the burglar and it was in the morning when he first sees him. Also, Tsuna had seemed to have shot and killed the burglar after waking up. Reborn had also placed a gun in Tsuna's hands, showing the 'evidence' that Tsuna's killing instincts has awaken.