Pablo created something he had used many times on Earth. He was proficient in it and many other weapons.
He could have created something more like a rocket launcher but he thought a Gatling gun would do more damage and it would attract the attention of the old man on the stage.
The old man still had his eyes closed and Pablo wanted to make the old man open his eyes. He wanted to stand out in the military.
So, to do that, he needed to make some noise. And for that noise, he manifested a Gatling Gun.
"A Bloody Gatling Gun? Is this a joke?"
"Haha. He is really delusional. Should we be afraid of this?"
"Aren't you embarrassed doing this, dick head?"
Everyone didn't take Pablo seriously but Pablo didn't worry about that. They didn't matter.
"How will you create bullets? What will you do with an empty gun?" Cupid asked. She had seen such things and she knew a gun needs bullets which Pablo didn't have.