No game has perfect AI, and the grunt's can be exploited to hilarious results, such as getting it to break down an open door, hiding behind a table in a corner, and piling up a bunch of stuff, then attracting its attention. That last one can occasionally cause it to smash it all, which then freezes it in search mode.
Anytime someone trolls the monsters. Also, replace the chase music with Yakety Sax and the monster sounds with the guy from Yelling At Cats.
Once Daniel enters the Cistern, a flashback occurs.
Daniel: You are conserving water from the spring? Alexander: Yes, it enables me to control the water in the drain sewers to some extent. Also, it can be used for all sorts of purposes. Daniel: Like for drinking?
The "Killings in Altstadt" custom game has parts where the player can buy items from a room which is run by a Grunt with an ushanka hat speaking in a Russian accent.