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...
This... This can't...
...هـ-هذا... هذا غير ممكن
D-Das … Das kann doch nicht …
No… ¡No…!
No… ¡No…!
Je peux pas finir comme ça !
No... Non può essere...
Não pode ser...
И что, всё зря?