The policeman at the gate says he's thirsty I'm wondering if I get anything from him and what do I need to give to him to drink.
>A policeman in the gate to Canalave City says "Boy... I sure am thirsty... ". This is a reference to the thirsty guards in the gates on Route 5, 6, 7, and 8, who prevented access to Saffron City in Generation I and Pokémon FireRed and LeafGreen. -Bulbapedia