Sorry, is this what you are asking (the size 25 is changed to 3 to illustrate)…
>>> a = torch.randn(3, 3, 3)
>>> a
tensor([[[ 0.0637, -0.7271,  0.9669],
         [-1.5508, -0.5795,  0.7472],
         [-0.9258,  0.6464,  0.7641]],

        [[-0.4879,  0.8104,  1.3433],
         [-0.3241, -1.3570, -0.2355],
         [ 2.1369,  0.1334,  1.2353]],

        [[-0.6005,  1.5156, -0.4654],
         [ 0.3012,  0.7669, -0.1073],
         [-0.2972,  0.2404, -1.3757]]])
>>> x = 1
>>> b = a[x, :, :].clone()
>>> b
tensor([[-0.4879,  0.8104,  1.3433],
        [-0.3241, -1.3570, -0.2355],
        [ 2.1369,  0.1334,  1.2353]])