Why wouldn't they believe him? If all they have experience with is magic, what else could they possibly think it is? Plus, magic is pretty diverse. You could totally have a magic-based gun. Same thing about Al and the hologram thing. He was just good at illusions
Retcon point: I had Ewa carry the vial of Vivalite out when she first left the room, so I'm gonna say there was either a second one lying around, or it has since fallen out of her pocket. Let me know.