Monsters in the game (A bit spoilerish?)

[Yuhaney]

They are smartly scripted, so we always found them disappear in thin air.

Well, at one point I started to follow one of the monsters and it stopped right in front of a door. I heard that it "left" the room which loads another level, but it just dissapeared in front of me (not the dust way, which was in the demo). Which I thought was pretty funny.

In my opinion, would be better if they at least stay in the room as long as we can see them and disappear when we're not seeing them (...or maybe it was just this one place that it happens).