During the defense of the Nautilus, Shoot the torpedos that the Jap planes have dropped in the water. I think there are four of them. When you first see the planes on the horizon try to take one out if you can, if not, after the reload, wait and shoot the torpedos before they hit the Nautilus, and mission accomplished.
When you board the USS West Virginia, after you get up to the second deck, there is another door that you can break open with your axe (it will be on the left in the hallway) and the ship's XO is injured in there. If you get him to a medic, it will be counted as a hero moment.
There is one unlockable medal on the Pearl Harbor mission. When you are running to your PT boat, pick up a wounded sailor and carry him to either the nurse or navy docter. do this 3x and get the medal. If you cant find enough sailors, just wait until some get shot by Zeros.in boot camp, you can recieve medals depending on your shooting accuracy, theres a 50%,75%,and 100% medal. If you get 100%, you will get all 3.