You have to go first with Maxine, in one of her dialogues, I don't quite remember which one unlocks something for you with the kitten, then you have to go with the cat and do what you unlocked, there he will give you the part of a spray, that joins it With an empty bottle, then you try to pour water on the bonsai in the infirmary and it won't work, then you go to the cafeteria and fill the spay bottle with the green drink, I think it was called 7 hp, with that if you partner with bonsai, I think the rest happens automatically