Heat the oil in a large skillet over medium-high heat. Add the garlic, scallion whites, and cook until fragrant, about 1 minute. Add the scallion greens and cook until softened, about 3 minutes. Push the veggies to the side and add the shrimp and cook for 3 minutes, flip, and cook another 1-2 minutes or until opaque. Push the shrimp and veggies to the side. Add the eggs in and scramble. Add the zucchini noodles into the skillet with the prepared sauce and toss to combine with the shrimp, veggies and eggs and let cook for 3-5 minutes or until zoodles are softened. While zoodles cook, in a small bowl, whisk together the arrowroot powder and water. Pour into the bottom of the pan and stir until thickened with the moisture in the bottom of the pan to create a thicker sauce. Toss everything together well to combine.