The person hiding in the mirror was Illuso from the Hitman Team. Fugo ends up being dragged into the mirror by Illuso's Stand, Mirrorman. Fugo then summons his own Stand, Purple Smoke. Despite Giorno wanting to find Fugo, Abbacchio decides to go look for the key, since that was their mission. However, once Abbacchio finds the key, he also gets dragged into the mirror world...
Mirror Man! Allow only me 
to leave this mirror!
!ميرور مان! اسمحْ لنفسي فقط بمغادرةِ هذه المرآة
Mirror Man! Erlaube nur mir,
den Spiegel zu verlassen!
¡Mirror Man! ¡Permite que solo yo
deje el espejo!
¡Mirror Man! ¡Permite que solo yo
deje el espejo!
Mirror Man, autorise-moi seul
à sortir du miroir !
Mirror Man! Dammi il permesso
di lasciare questo specchio!
Mirror Man! Permita a saída do espelho
exclusivamente pra mim!
Мэн ин де Миррор!