Sniper Elite 4

For this achievement, Hitler must be alerted to your presence. While attempting to escape, he will run in a number of directions and eventually make it out to the dock where he will jump into a boat and drive away. Before alerting him, you need to shoot down a couple of sea mines that are suspended over the water, so when he drives past one, you can shoot it to cause an explosion and kill him.

This achievement starts at [6:02] in AFGuidesHD’s video.