The distance between two points $P(x_1, y_1)$ and $Q(x_2, y_2)$ is given by the formula:
\[
d = \sqrt{(x_2 - x_1)^2 + (y_2 - y_1)^2}
\]
For the points $P(2, -3)$ and $Q(10, v)$, the distance is given as 10 units:
\[
10 = \sqrt{(10 - 2)^2 + (v - (-3))^2}
\]
\[
10 = \sqrt{8^2 + (v + 3)^2}
\]
\[
10 = \sqrt{64 + (v + 3)^2}
\]
\[
100 = 64 + (v + 3)^2
\]
\[
(v + 3)^2 = 36
\]
\[
v + 3 = \pm 6
\]
So,
\[
v = 6 - 3 = 3 \quad \text{or} \quad v = -6 - 3 = -9
\]
Thus, the values of $v$ are $9$ and $3$.