As the man and the other people wearing rabbit masks walked down the corridor, they occasionally split up to go somewhere different. Until eventually, they had all split up from each other.
Then, one after another, people with rabbit masks appeared on the surface. Some of them came out of people's houses. Others came out of a lake. Then there were people that actually just burst out of the ground.
Regardless, they were sprouting up like actual rabbits.
The rabbit masks were rather conspicuous, so most of the passersby noticed them. However, most came to the conclusion that it was just a strange person when there was only one.
It was only when they started to group up, showing multiple people with the same mask, did the passerby realize something was wrong. There was one that decided to report this strange group of people to the council.