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...
Giorno Giovanna... That brat 
doesn't understand anything!
جورنو جوفانا... ذاك الطّفل لا يفهم شيئاً
Giorno Giovanna … Das Balg hat auch
mal wieder gar nichts verstanden.
Giorno Giovanna…
¡Ese mocoso no entiende nada!
Giorno Giovanna…
¡Ese mocoso no entiende nada!
Giorno Giovanna…
Ce gamin pige rien à rien !
Giorno Giovanna... Quel
moccioso non capisce niente!
Giorno Giovanna...
Esse moleque não sabe de nada!
Джорно Джованна! 
Этот сопляк… так ничего и не понял!