Heat a large skillet on low-medium flame. In a large bowl whisk eggs until blended, then add the milk, mayo, salt, and pepper. Spray skillet with non-stick cooking spray, add egg mixture. Wait about 30-40 seconds then start from the edges of the pan, with a spatula, making your way into the middle of the pan scrambling the eggs. Keep scrambling until firm. Turn off flame. Lay the slice of Swiss on top of the eggs and wait until it is melted then mix by gently tossing until cheesy.