Yeah, that's been one of my gripes with this game as well. There is no way to see them coming. Shooting at the sky when you hear a dragon roar? Just a fight. Getting a random blowjob? Unavoidable death. You hear a door opening - Hide? Death. Wait? Just a fight. Check it out? Death. Run? Just a fight.instant death situations.
These kinds of deaths really just tempt the player to reload a save, which isn't good game design.