i´m not sure but actually, when you drop the egg on the rice, he is so hot that the egg kinda "auto-cook", or its a similar recipe, try youtube, there are people that teach this recipe.
There is nothing wrong with a raw egg. When I was young my mom used to make hot drink with raw egg, honey and stuff and it was very delicious. Also I didn't see anywhere eat raw eggs with rice outside Japan, but we used to eat them raw in Vietnam (no from the fridge, normal raw egg, sometimes right after the hen deliver them) Super high protein.
The thing is is that eggs inside Japan are mostly designed to be eaten raw. In the states, the eggs are designed to be more clean than fresh, so eating it raw would give you a stomach ache. A really bad one...