i want to extract np.mean from array using coordinates from another array,same size

Question

arr2=np.array([[65,53,73,53,14,],[46,70,72,19,32],[22,76,29,55,61],[35,74,24,32,78]],dtype="int16")

arr4 array([[[0, 4], [1, 3], [1, 4], [2, 0], [2, 2], [3, 0