A implicação é que Cornelius e Leeloo removeram o número da unidade quando chegaram ao Korben's e colocaram o cartão de Korben na porta do vizinho.
De o script :
Leeloo and Cornelius search for Korben's apartment. Leeloo carries the card Korben gave her. Cornelius finds the apartment, and yanks the. number off the door. He waves Leeloo over as his hand goes to the bell.
(recorte)
C.U. Korben's calling card is clumsily stuck to the door of the neighbor's apartment. COP 3 slaps the viewer on the nasty neighbor's door. The neighbor is at his sink shaving instead of against the wall, COP 1 arrives with Korben's picture.
Você pode ver o cartão preso na porta do vizinho na cena.