Meta Knight usually throws a sword towards Kirby and doesn't start the fight until he picks it up. Kirby is tired of his shit and pulls out a gun. Meta Knight was prepared.
Just to add on, in the original game, you can't start the battle (Metaknight won't take damage) until you take the sword that has that big sign over it. It's rather annoying if you have and prefer to use a different power, you have to take the sword.
