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...
Fugo, you're basically done for already.
فوغو، لقد تمَّ تولِّي أمرك جوهريّاً
Fugo, mit dir bin ich dann fertig.
Fugo, ya estás prácticamente acabado.
Fugo, ya estás prácticamente acabado.
Fugo, t’es complètement ruiné.
Fugo, per ora ti lascerò qui,
tanto ormai non puoi più fare danni.
Fugo, você já está praticamente vencido.
Фуго, ты в любом случае не жилец.