Everyone knows there is vermin crawling around in the Montreal metro system. Sometimes it's a rat, sometimes it's a mouse, and sometimes it's a guy who just wants to show you his penis.
But knowing they exist and actually seeing them are two very different things.
I know there are rats and mice in the metro. It's underground after all. But that's doesn't mean I expect to see 4 of them casually hanging out on the platform of the Cote-des-Neiges Metro.