In the previous episode, he acted crazy when he found out that he has only seven days to live. First off, the serial is highly flawed because if he has only seven days to live, he wouldn’t be strong enough to do silly bike stunts in his own house. Not to mention how he plans to deal with his death, by making his family dislike him to the extent of them not missing him when he dies.
Logic seems to have committed suicide in this bit. But we’ll stick to what has happened and what is about to happen on the show. So in the previous episode, Shivansh learns that he has only seven days to live. He, therefore, decides to make sure his family doesn’t suffer a lot from his death. He plans to hurt them and make them hate him so much that they won’t miss him when he dies. He also plans to get rid of Mannat within seven days.