I was in Hillgrund's Tomb with Lydia and Golldir. We went into a small chamber to kill a standing asleep draugr and Lydia did what Lydia does best... stood in the doorway. I jump over her shoulder and immediately go back into sneak mode forcing Lydia and Golldir into sneak mode as well. I look back to see how they are doing and they are nose to nose in sneak mode with Lydia blocking the door and Golldir stuck on the inside.
Then out of the blue Golldir shield bashed Lydia in the nose.
They fight.
Curious I back up and watch and I was surprised when Golldir killed her. Dead. Just like that, there she lay. Taken down by a milk drinker.
(A draugr had come up by that time and was firing some ice attack on them, I shot the draugr so they could finish their fight, but Golldir sent her to her knees and she still was all frosty from the draugr still. I discovered that effects such as poison or ice will still work when a follower goes to their knees and that must have been what finished her off. )
Everytiime I pass one of those swinging gate traps I always turn to watch my follower get smashed. I get disappointed when they somehow manage to miss the trigger. I will miss watching Lydia get smashed.