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...
Assuming that's even possible.
إن كان ذلك مُمكِناً أصلاً
Wenn das überhaupt
möglich ist.
¿Es posible siquiera?
¿Es posible siquiera?
Si ça existe, tout s’explique.
Dando per buono che una cosa
del genere sia possibile...
Eu nem sabia que isso era possível...
если допустить, что такое возможно.