When the guy accidentally shot the guest with the revolver and then throws it over the roof it discharges when it hits the ground. A revolver that had just been fired could not fire again without the cylinder being rotated to place a live round under the hammer.
When Delko's mother show Eric his birth certificate, it says "Certificado de Necimiento". The producers could know very easily that birth in Spanish is 'Nacimiento', but they chose not to use a dictionary.