Two times for me...
1) In some cave, I think the one with the dead Akaviri Messenger in it, and I turned at a T intersection, and the place I came from had the roof collapse behind me, no choice but to go on, so I turned the T intersection to the left and came to a corner when I heard heavy stomping behind me, I turned around and there is an Ogre! Too close to use my bow, I ran around the corner, hoping to get some ground between it and me, then around the corner is two more Ogres! Thankyou Goldbrand...
2) I was doing DB questline, returned to Luciens new farmhouse, when I found him hanging naked, mutilated, upside down from the roof! And he was surrounded by creepy people in Black Robes! Yeah, i kinda attacked them.... Then went back to a save