Assuming we have two programs $p_1$ and $p_2$ and two line numbers $n_1$ and $n_2$. Does $p_1$ reach $n_1$ in less computational steps than $p_2$ reaches $n_2$? By reduction from Halting, this is clearly not decidable, but I think it is semi decidable.
To do so, I would build an interpreter, that executes $p_1$ and $p_2$ simultaneously step by step and count the steps for each program. As soon as $p_1$ reaches $n_1$, I compare the number of steps to $n_2$ and return true if it is less. If $p_2$ reaches $n_2$ first, I return false. In case no program reaches $n_1$ or $n_2$, nothing happens (following semi-decidability).